diff --git a/config/default.json b/config/default.json
index 21b7af6..c274bb2 100644
--- a/config/default.json
+++ b/config/default.json
@@ -1,71 +1,71 @@
 {
     "containers": {
       "id": {
           "implementations": "impl_fulfill_cluster",
           "clusters": "var_cluster",
           "prototypes": "proto_cluster",
           "linkedlist": "linkedlist"
       }, 
       
       "impl": {
         "solid": "solid",
         "onthefly": "on_the_fly"
       }
     },
     
     "logging": {
       "id": "logging"
     },
     
     "function-entry": "entry",
     
     "clasp": {
       "bindings" : {
         "variable": "bind",
         "function": "bind_func",
         "scope": "bind_scope",
         "function_demand" : "bind_function_demand",
         "scope_decision": "bind_scope_decision"
       },
       
       "context" : {
         "decisions":{
             "dependent": "resolution_dependency"
         }
       }, 
       
       "nonevalue": "nonevalue",
       "ret": {
         "symbol": "retv",
         "tag": "ret"
       } 
     },
     
     "tests": { 
-      "template": "communication",
+      "template": "compilation",
       
       "templates": {
         "default": "*-Adhoc.*:Compilation.full_IFStatementWithVariantType:Types.full_VariantType_Switch1",
         "ast": "AST.*",
         "adhocs": "Adhoc.*",
         "effects": "Effects.*",
         "basic": "Attachments.*", 
         "context": "Context.*",
-        "compilation": "Compilation.*",
+        "compilation": "Compilation.full_SwitchVariant1",
         "communication": "Communication.FullDirectAndGuarded1",
         "cfa": "CFA.*",
         "containers": "Containers.*",
         "dfa": "DFA.*",
         "diagnostic": "Diagnostic.*",
         "dsl": "Interpretation.SwitchVariantAlias-Association.*",
         "ExpressionSerializer": "ExpressionSerializer.*",
         "externc": "InterfaceExternC.*",
         "loops": "Loop.*",
         "modules": "Modules.*",
         "polymorphs": "Polymorphs.call1",
         "types": "Types.*",       
         "vendorsAPI/clang": "ClangAPI.*",
         "vendorsAPI/xml2": "libxml2*"
       }
     }
 }
diff --git a/cpp/src/CMakeLists.txt b/cpp/src/CMakeLists.txt
index 3a19723..6c98f92 100644
--- a/cpp/src/CMakeLists.txt
+++ b/cpp/src/CMakeLists.txt
@@ -1,230 +1,230 @@
 cmake_minimum_required(VERSION 2.8.11)
 project(xreate)
 cmake_policy(SET CMP0022 NEW)
 
 message("MODULES" ${CMAKE_MODULE_PATH})
 
 #       LLVM
 #======================
 FIND_PACKAGE (LLVM REQUIRED)
 set(LLVM_VERSION ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR})
 
 message(STATUS "Found LLVM ${LLVM_PACKAGE_VERSION}")
 message("LLVM LIB PATH:" ${LLVM_LIBRARY_DIRS})
 message(STATUS "Using LLVMConfig.cmake in: ${LLVM_DIR}")
 
 INCLUDE_DIRECTORIES(${LLVM_INCLUDE_DIRS})
 message(STATUS "INCLUDE DIR: ${LLVM_INCLUDE_DIRS}")
 
 add_definitions(${LLVM_DEFINITIONS})
 message("LLVM DEFS: " ${LLVM_DEFINITIONS})
 
 llvm_map_components_to_libnames(LLVM_LIBS core nativecodegen native executionengine mcjit support option)
 message("LLVM LIBS: " ${LLVM_LIBS})
 
 
 
 #       CLANG
 #======================
 set(CLANG_LIBS
 	clangCodeGen 
 	clangASTMatchers
 	clangQuery
 	clangTooling
 	clangFrontend
 	clangSerialization
 	clangDriver
 	clangParse
 	clangSema
 	clangAnalysis
 	clangAST
 	clangEdit
 	clangLex
 	clangBasic	
 )
 
 
 
 #       POTASSCO
 #======================
 set(POTASSCO_PATH "/opt/potassco/clingo" CACHE PATH "Path to potassco sources")
 set(POTASSCO_INCLUDE_PATH
     ${POTASSCO_PATH}/libgringo
     ${POTASSCO_PATH}/libclasp
     ${POTASSCO_PATH}/libclingo
     ${POTASSCO_PATH}/libprogram_opts
     ${POTASSCO_PATH}/liblp
 )
 INCLUDE_DIRECTORIES(${POTASSCO_INCLUDE_PATH})
 set(LIBCLASP_LIBS
     clingo
     clasp
     gringo
     program_opts
     reify
     lp
 )
 message("CLASP LIBS: " ${LIBCLASP_LIBS})
 
 
 
 #       OTHER DEPENDENCIES
 #===========================
 set(JEAYESON_INCLUDE_PATH
     ${CMAKE_HOME_DIRECTORY}/../vendors/jeayeson/include/
 )
 INCLUDE_DIRECTORIES(${JEAYESON_INCLUDE_PATH})
 
 
 
 #       COCO
 #===========================
 
 set(COCO_EXECUTABLE "" CACHE PATH "Path to coco executable")
 set(COCO_FRAMES_PATH "" CACHE PATH "Path to coco frames")
 
 set(COCO_GRAMMAR_PATH ${CMAKE_HOME_DIRECTORY}/../grammar/)
 set(COCO_SOURCE_FILES_MAIN
         ${COCO_GRAMMAR_PATH}/main/Parser.cpp
         ${COCO_GRAMMAR_PATH}/main/Scanner.cpp
 )
 
 set(COCO_SOURCE_FILES_MODULES
         ${COCO_GRAMMAR_PATH}/modules/Parser.cpp
         ${COCO_GRAMMAR_PATH}/modules/Scanner.cpp
 )
 
 set(COCO_SOURCE_FILES ${COCO_SOURCE_FILES_MODULES} ${COCO_SOURCE_FILES_MAIN})
 
 INCLUDE_DIRECTORIES(${COCO_GRAMMAR_PATH})
 
 add_custom_command(OUTPUT ${COCO_SOURCE_FILES_MAIN}
     COMMAND ${COCO_GRAMMAR_PATH}/gen-grammar main ${COCO_EXECUTABLE} ${COCO_FRAMES_PATH}
     WORKING_DIRECTORY ${COCO_GRAMMAR_PATH}
     MAIN_DEPENDENCY ${COCO_GRAMMAR_PATH}/xreate.ATG   
 )
 
 add_custom_command(OUTPUT ${COCO_SOURCE_FILES_MODULES}
     COMMAND ${COCO_GRAMMAR_PATH}/gen-grammar modules ${COCO_EXECUTABLE} ${COCO_FRAMES_PATH}
     WORKING_DIRECTORY ${COCO_GRAMMAR_PATH}
     MAIN_DEPENDENCY ${COCO_GRAMMAR_PATH}/modules.ATG
 )
 
 message(STATUS "COCO GRAMMAR BUILD STATUS:" ${COCO_OUTPUT})
 
 
 
 #       XREATE
 #======================
 set(SOURCE_FILES
     query/polymorph.cpp
     analysis/dfagraph.cpp
     pass/dfapass.cpp 
     compilation/targetinterpretation.cpp
     pass/interpretationpass.cpp
     ast.cpp
     xreatemanager.cpp
     analysis/typeinference.cpp
     aux/xreatemanager-decorators.cpp
     compilation/operators.cpp
     compilation/transformations.cpp
     compilation/transformersaturation.cpp
     pass/compilepass.cpp 
     pass/versionspass.cpp
     attachments.cpp
     ExternLayer.cpp 
     analysis/cfagraph.cpp
     analysis/aux.cpp
     compilation/containers.cpp
-    compilation/advanced.cpp
+    compilation/advancedinstructions.cpp
     clasplayer.cpp
     compilation/latecontextcompiler2.cpp
     query/context.cpp
     llvmlayer.cpp 
     utils.cpp
     pass/abstractpass.cpp 
     pass/cfapass.cpp
     pass/adhocpass.cpp
     contextrule.cpp
     query/containers.cpp
     analysis/DominatorsTreeAnalysisProvider.cpp
     aux/serialization/expressionserializer.cpp
     modules.cpp
 )
 
 set(XREATE_INCLUDE_DIRS
     ${CMAKE_CURRENT_SOURCE_DIR}/
 )
 
 INCLUDE_DIRECTORIES(${XREATE_INCLUDE_DIRS})
 
 set(XREATE_PRIVATE_INCLUDE_DIRS
     ${XREATE_INCLUDE_DIRS}
     ${COCO_GRAMMAR_PATH}
     ${JEAYESON_INCLUDE_PATH}
     ${LLVM_INCLUDE_DIRS}
     ${POTASSCO_INCLUDE_PATH}
 )
 
 add_library(${PROJECT_NAME} SHARED ${COCO_SOURCE_FILES} ${SOURCE_FILES})
 
 target_link_libraries(${PROJECT_NAME})
 
 
 target_include_directories(${PROJECT_NAME} INTERFACE 
     ${XREATE_INCLUDE_DIRS}
     ${COCO_GRAMMAR_PATH}
     ${JEAYESON_INCLUDE_PATH}
     ${LLVM_INCLUDE_DIRS}
     ${POTASSCO_INCLUDE_PATH}
 )
 
 get_directory_property(DEFINITIONS_ALL DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR} COMPILE_DEFINITIONS)
 message("definitions all: " ${DEFINITIONS_ALL})
 target_compile_definitions(${PROJECT_NAME} INTERFACE ${DEFINITIONS_ALL})
 
 get_directory_property(COMPILATION_OPTIONS_ALL DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR} COMPILE_OPTIONS)
 message("compilations all: " ${COMPILATION_OPTIONS_ALL})
 target_compile_options(${PROJECT_NAME} INTERFACE ${COMPILATION_OPTIONS_ALL})
 
 SET_PROPERTY(TARGET ${PROJECT_NAME} PROPERTY
     INTERFACE_LINK_LIBRARIES ${LIBCLASP_LIBS} ${CLANG_LIBS} ${LLVM_LIBS} tbb boost_system boost_filesystem 
 )
 
 #${CLANG_LIBS}
 
 
 #set (LINK_INTERFACE_LIBRARIES "")
 
 # FUNCTION(PREPEND var prefix)
 #    SET(listVar "")
 #    FOREACH(f ${ARGN})
 #       LIST(APPEND listVar "${prefix}/${f}")
 #    ENDFOREACH(f)
 #    SET(${var} "${listVar}" PARENT_SCOPE)
 # ENDFUNCTION(PREPEND)
 
 #set(COTIRE_UNITY_SOURCE_MAXIMUM_NUMBER_OF_INCLUDES "-j4")
 #cotire(xreate)
 
 
 # MACRO (ADD_PCH_RULE  _header_filename _src_list)
 # 	SET(_gch_filename "${_header_filename}.gch")
 # 	LIST(APPEND ${_src_list} ${_gch_filename})
 # 	SET (_args ${CMAKE_CXX_FLAGS})
 # 	LIST(APPEND _args -c ${_header_filename} -o ${_gch_filename})
 # 	GET_DIRECTORY_PROPERTY(DIRINC INCLUDE_DIRECTORIES)
 # 	foreach (_inc ${DIRINC})
 # 		LIST(APPEND _args "-I" ${_inc})
 # 	endforeach(_inc ${DIRINC})
 # 	SEPARATE_ARGUMENTS(_args)
 # 	add_custom_command(OUTPUT ${_gch_filename}
 # 		   COMMAND rm -f ${_gch_filename}
 # 		   COMMAND ${CMAKE_CXX_COMPILER} ${CMAKE_CXX_COMPILER_ARG1} ${_args}
 # 			    DEPENDS ${_header_filename})
 # ENDMACRO(ADD_PCH_RULE _header_filename _src_list)
 
 # ADD_PCH_RULE (${CMAKE_HOME_DIRECTORY}/src/ast.h SOURCE_FILES)
 # ADD_PCH_RULE (${CMAKE_HOME_DIRECTORY}/src/llvmlayer.h SOURCE_FILES)
 # ADD_PCH_RULE (${CMAKE_HOME_DIRECTORY}/src/clasplayer.h SOURCE_FILES)
 # ADD_PCH_RULE (${CMAKE_HOME_DIRECTORY}/src/pass/abstractpass.h SOURCE_FILES)
diff --git a/cpp/src/analysis/typeinference.cpp b/cpp/src/analysis/typeinference.cpp
index ec38c58..17d2a1f 100644
--- a/cpp/src/analysis/typeinference.cpp
+++ b/cpp/src/analysis/typeinference.cpp
@@ -1,68 +1,72 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * typeinference.cpp
  *
  * Author: pgess <v.melnychenko@xreate.org>
  * Created on April 16, 2017, 10:13 AM
  */
 
 /**
  *  \file typeinference.h
  *  \brief Type inference analysis
  */
 
 #include "typeinference.h"
 #include "llvmlayer.h"
 
 #include "llvm/IR/Function.h"
 #include "llvm/IR/DerivedTypes.h"
 
 namespace xreate {namespace typeinference {
 
 //TODO type conversion:
 //a)    automatically expand types int -> bigger int; int -> floating
 //b)    detect exact type of `num` based on max used numeral / function type
 //c)    warning if need to truncate (allow/dissalow based on annotations)
 
 llvm::Value*
 doAutomaticTypeConversion(llvm::Value* source, llvm::Type* tyTarget, llvm::IRBuilder<>& builder){
     if (tyTarget->isIntegerTy() && source->getType()->isIntegerTy())
     {
             llvm::IntegerType* tyTargetInt = llvm::dyn_cast<llvm::IntegerType>(tyTarget);
             llvm::IntegerType* tySourceInt = llvm::dyn_cast<llvm::IntegerType>(source->getType());
 
             if (tyTargetInt->getBitWidth() < tySourceInt->getBitWidth()){
                     return builder.CreateCast(llvm::Instruction::Trunc, source, tyTarget);
             }
 
             if (tyTargetInt->getBitWidth() > tySourceInt->getBitWidth()){
                     return builder.CreateCast(llvm::Instruction::SExt, source, tyTarget);
             }
     }
 
     if (source->getType()->isIntegerTy() && tyTarget->isFloatingPointTy()){
         return builder.CreateCast(llvm::Instruction::SIToFP, source, tyTarget);
     }
 
     return source;
 }
 
 ExpandedType
 getType(const Expression& expression, const AST& ast){
     if (expression.type.isValid()){
             return ast.expandType(expression.type);
     }
 
     if (expression.__state == Expression::IDENT){
         Symbol s = Attachments::get<IdentifierSymbol>(expression);
         return getType(CodeScope::getDefinition(s), ast);
     }
 
+    if (Attachments::exists<TypeInferred>(expression)){
+        return Attachments::get<TypeInferred>(expression);
+    }
+
     assert(false && "Type can't be determined for an expression");
 }
 
 
 
 } } //end of namespace xreate::typeinference
diff --git a/cpp/src/ast.cpp b/cpp/src/ast.cpp
index 70c3923..692db6a 100644
--- a/cpp/src/ast.cpp
+++ b/cpp/src/ast.cpp
@@ -1,976 +1,979 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * Author: pgess <v.melnychenko@xreate.org>
  * File: ast.cpp
  */
 
 /**
  * \file    ast.h
  * \brief   Syntax Tree and related code
  *
  * \sa xreate::AST
  */
 
 #include "ast.h"
 #include "ExternLayer.h"
 #include "analysis/typeinference.h"
 
 #include <stdexcept>
 #include <iostream>
 
 //TODO BDecl. forbid multiple body declaration (ExprTyped)
 
 namespace std {
 
     std::size_t
     hash<xreate::ScopedSymbol>::operator()(xreate::ScopedSymbol const& s) const {
         return s.id ^ (s.version << 2);
     }
 
     bool
     equal_to<xreate::ScopedSymbol>::operator()(const xreate::ScopedSymbol& __x, const xreate::ScopedSymbol& __y) const {
         return __x.id == __y.id && __x.version == __y.version;
     }
 
     size_t
     hash<xreate::Symbol>::operator()(xreate::Symbol const& s) const {
         return hash<xreate::ScopedSymbol>()(s.identifier) ^ ((long int) s.scope << 1);
     }
 
     bool
     equal_to<xreate::Symbol>::operator()(const xreate::Symbol& __x, const xreate::Symbol& __y) const {
         return __x == __y;
     };
 }
 
 using namespace std;
 
 namespace xreate {
 
 Atom<Identifier_t>::Atom(const std::wstring& value) {
     __value = wstring_to_utf8(value);
 }
 
 Atom<Identifier_t>::Atom(std::string && name) : __value(name) {
 }
 
 const std::string&
 Atom<Identifier_t>::get() const {
     return __value;
 }
 
 Atom<Number_t>::Atom(wchar_t* value) {
     //DEBT reconsider number literal recognition
     __value = wcstol(value, 0, 10);
 }
 
 Atom<Number_t>::Atom(int value)
 : __value(value) {
 }
 
 double
 Atom<Number_t>::get()const {
     return __value;
 }
 
 Atom<String_t>::Atom(const std::wstring& value) {
     assert(value.size() >= 2);
     __value = wstring_to_utf8(value.substr(1, value.size() - 2));
 }
 
 Atom<String_t>::Atom(std::string && name) : __value(name) {}
 
 const std::string&
 Atom<String_t>::get() const {
     return __value;
 }
 
 class ExpressionHints {
 public:
 
     static bool
     isStringValueValid(const Expression& e) {
         switch (e.__state) {
             case Expression::INVALID:
                 assert(false);
 
             case Expression::IDENT:
             case Expression::STRING:
                 return true;
 
             case Expression::NUMBER:
             case Expression::BINDING:
                 return false;
 
             case Expression::COMPOUND:
             {
                 switch (e.op) {
                     case Operator::CALL:
                         return true;
 
                     default: return false;
                 }
             }
         }
 
         return false;
     }
 
     static bool
     isDoubleValueValid(const Expression& e) {
         switch (e.__state) {
             case Expression::NUMBER:
                 return true;
 
             case Expression::INVALID:
                 assert(false);
 
             case Expression::IDENT:
             case Expression::STRING:
             case Expression::BINDING:
                 return false;
 
             case Expression::COMPOUND: {
                 switch (e.op) {
                     case Operator::VARIANT:
                         return true;
                     default: return false;
                 }
             }
         }
 
         return false;
     }
 };
 
 class TypesResolver {
 private:
     const AST* ast;
     std::map<std::string, TypeAnnotation> scope;
     std::map<TypeAnnotation, int> signatures;
 
     ExpandedType expandType(const TypeAnnotation &t, const std::vector<TypeAnnotation> &args = std::vector<TypeAnnotation>()) {
         return TypesResolver(ast, scope, signatures)(t, args);
     }
 
     std::vector<TypeAnnotation>
     expandOperands(const std::vector<TypeAnnotation>& operands) {
         std::vector<TypeAnnotation> pack;
 
         pack.reserve(operands.size());
         std::transform(operands.begin(), operands.end(), std::inserter(pack, pack.end()),
                 [this](const TypeAnnotation & t) {
                     return expandType(t);
                 });
 
         return pack;
     }
 
 public:
 
     TypesResolver(const AST* root, const std::map<std::string, TypeAnnotation>& scopeOuter = std::map<std::string, TypeAnnotation>(),
             std::map<TypeAnnotation, int> signaturesOuter = std::map<TypeAnnotation, int>())
     : ast(root), scope(scopeOuter), signatures(signaturesOuter) {
     }
 
     ExpandedType
     operator()(const TypeAnnotation &t, const std::vector<TypeAnnotation> &args = std::vector<TypeAnnotation>()) {
         //assert(args.size() == t.bindings.size()); // invalid number of arguments
         for (size_t i = 0; i < args.size(); ++i) {
             scope[t.bindings.at(i)] = args.at(i);
         }
 
         switch (t.__operator) {
             case TypeOperator::ARRAY:
             {
                 assert(t.__operands.size() == 1);
 
                 Expanded<TypeAnnotation> elTy = expandType(t.__operands.at(0));
                 return ExpandedType(TypeAnnotation(tag_array, elTy, 0));
             }
 
             case TypeOperator::STRUCT:
             {
-                assert(t.__operands.size());
-
                 std::vector<TypeAnnotation>&& packOperands = expandOperands(t.__operands);
                 auto typNew = TypeAnnotation(TypeOperator::STRUCT, move(packOperands));
                 typNew.fields = t.fields;
 
                 return ExpandedType(move(typNew));
             };
 
+            case TypeOperator::VARIANT:
+            {
+                std::vector<TypeAnnotation>&& packOperands = expandOperands(t.__operands);
+                auto typNew = TypeAnnotation(TypeOperator::VARIANT, move(packOperands));
+                typNew.fields = t.fields;
+
+                return ExpandedType(move(typNew));
+            };
+
             case TypeOperator::CALL:
             {
                 std::string alias = t.__valueCustom;
 
                 //find in local scope:
                 TypeAnnotation ty;
                 if (scope.count(alias)) {
                     ty = scope.at(alias);
 
                 } else if (ast->__indexTypeAliases.count(alias)) {
                     ty = ast->__indexTypeAliases.at(alias);
 
                 } else {
                     assert(false && "Undefined or external type");
                 }
 
                 std::vector<TypeAnnotation>&& operands = expandOperands(t.__operands);
                 TypeAnnotation signature(TypeOperator::CALL, move(operands));
                 signature.__valueCustom = alias;
 
                 if (signatures.count(signature)) {
                     auto link = TypeAnnotation(TypeOperator::LINK,{});
                     link.conjuctionId = signatures.at(signature);
 
                     return ExpandedType(move(link));
                 }
 
                 int cid = signatures.size();
                 signatures[signature] = cid;
                 TypeAnnotation tyResult = expandType(ty, operands);
                 tyResult.conjuctionId = cid;
 
                 return ExpandedType(move(tyResult));
             };
 
             case TypeOperator::CUSTOM:
             {
                 std::string alias = t.__valueCustom;
 
                 /*
                 if (signatures.count(alias)) {
                     return ExpandedType(TypeAnnotation(TypeOperator::LINK, {t}));
                 }
                 signatures[alias].emplace(t);
                  */
 
                 //find in local scope:
                 if (scope.count(alias)) {
                     return expandType(scope.at(alias));
                 }
 
                 // find in general scope:
                 if (ast->__indexTypeAliases.count(alias)) {
                     return expandType(ast->__indexTypeAliases.at(t.__valueCustom));
                 }
 
                 //if type is unknown keep it as is.
                 return ExpandedType(TypeAnnotation(t));
             };
 
             case TypeOperator::ACCESS:
             {
                 std::string alias = t.__valueCustom;
                 ExpandedType tyAlias = ExpandedType(TypeAnnotation());
 
                 //find in local scope:
                 if (scope.count(alias)) {
                     tyAlias = expandType(scope.at(alias));
 
                     //find in global scope:
                 } else if ((ast->__indexTypeAliases.count(alias))) {
                     tyAlias = expandType(ast->__indexTypeAliases.at(alias));
 
                 } else {
                     assert(false && "Undefined or external type");
                 }
 
                 assert(tyAlias->__operator == TypeOperator::STRUCT);
 
                 for (const string& field : t.fields) {
                     auto fieldIt = std::find(tyAlias->fields.begin(), tyAlias->fields.end(), field);
                     assert(fieldIt != tyAlias->fields.end() && "unknown field");
 
                     int fieldId = fieldIt - tyAlias->fields.begin();
                     tyAlias = expandType(tyAlias->__operands.at(fieldId));
                 }
 
                 return tyAlias;
             }
 
-            case TypeOperator::VARIANT:
-            {
-                return ExpandedType(TypeAnnotation(t));
-            }
-
             case TypeOperator::NONE:
             {
                 return ExpandedType(TypeAnnotation(t));
             }
 
             default:
                 assert(false);
         }
 
         assert(false);
         return ExpandedType(TypeAnnotation());
     }
 };
 
 TypeAnnotation::TypeAnnotation()
 : __operator(TypeOperator::NONE), __value(TypePrimitive::Invalid) {
 }
 
 TypeAnnotation::TypeAnnotation(TypePrimitive typ)
 : __value(typ) {
 }
 
 TypeAnnotation::TypeAnnotation(TypeOperator op, std::initializer_list<TypeAnnotation> operands)
 : __operator(op), __operands(operands) {
 
 }
 
 TypeAnnotation::TypeAnnotation(TypeOperator op, std::vector<TypeAnnotation>&& operands)
 : __operator(op), __operands(operands) {
 }
 
 TypeAnnotation::TypeAnnotation(llvm_array_tag, TypeAnnotation typ, int size)
 : TypeAnnotation(TypeOperator::ARRAY,{typ}) {
     __size = size;
 }
 
 bool
 TypeAnnotation::isValid() const {
     return !(__value == TypePrimitive::Invalid && __operator == TypeOperator::NONE);
 }
 
 bool
 TypeAnnotation::operator<(const TypeAnnotation& t) const {
     if (__operator != t.__operator) return __operator < t.__operator;
 
     if (__operator == TypeOperator::NONE)
         return __value < t.__value;
 
     if (__operator == TypeOperator::CALL || __operator == TypeOperator::CUSTOM || __operator == TypeOperator::ACCESS) {
         if (__valueCustom != t.__valueCustom)
             return __valueCustom < t.__valueCustom;
     }
 
     return __operands < t.__operands;
 }
 
 /*
 TypeAnnotation (struct_tag, std::initializer_list<TypeAnnotation>)
 {}
  */
 
 void
 TypeAnnotation::addBindings(std::vector<Atom<Identifier_t>>&& params) {
     bindings.reserve(bindings.size() + params.size());
 
     std::transform(params.begin(), params.end(), std::inserter(bindings, bindings.end()),
             [](const Atom<Identifier_t>& ident) {
                 return ident.get(); });
 }
 
 void
 TypeAnnotation::addFields(std::vector<Atom<Identifier_t>>&& listFields) {
     fields.reserve(fields.size() + listFields.size());
 
     std::transform(listFields.begin(), listFields.end(), std::inserter(fields, fields.end()),
             [](const Atom<Identifier_t>& ident) {
                 return ident.get(); });
 }
 
 unsigned int Expression::nextVacantId = 0;
 
 Expression::Expression(const Atom<Number_t>& number)
 : Expression() {
     __state = NUMBER;
     op = Operator::NONE;
     __valueD = number.get();
 }
 
 Expression::Expression(const Atom<String_t>& a)
 : Expression() {
     __state = STRING;
     op = Operator::NONE;
     __valueS = a.get();
 }
 
 Expression::Expression(const Atom<Identifier_t> &ident)
 : Expression() {
     __state = IDENT;
     op = Operator::NONE;
     __valueS = ident.get();
 }
 
 Expression::Expression(const Operator &oprt, std::initializer_list<Expression> params)
 : Expression() {
     __state = COMPOUND;
     op = oprt;
 
     if (op == Operator::CALL) {
         assert(params.size() > 0);
         Expression arg = *params.begin();
 
         assert(arg.__state == Expression::IDENT);
         __valueS = std::move(arg.__valueS);
 
         operands.insert(operands.end(), params.begin() + 1, params.end());
         return;
     }
 
     operands.insert(operands.end(), params.begin(), params.end());
 }
 
 void
 Expression::setOp(Operator oprt) {
     op = oprt;
 
     switch (op) {
         case Operator::NONE:
             __state = INVALID;
             break;
 
         default:
             __state = COMPOUND;
             break;
     }
 }
 
 void
 Expression::addArg(Expression &&arg) {
     operands.push_back(arg);
 }
 
 void
 Expression::addTags(const std::list<Expression> tags) const {
     std::transform(tags.begin(), tags.end(), std::inserter(this->tags, this->tags.end()),
             [](const Expression & tag) {
                 return make_pair(tag.getValueString(), tag);
             });
 }
 
 void
 Expression::addBindings(std::initializer_list<Atom<Identifier_t>> params) {
     addBindings(params.begin(), params.end());
 }
 
 void
 Expression::bindType(TypeAnnotation t) {
     type = move(t);
 }
 
 void
 Expression::addBlock(ManagedScpPtr scope) {
     blocks.push_back(scope.operator->());
 }
 
 const std::vector<Expression>&
 Expression::getOperands() const {
     return operands;
 }
 
 double
 Expression::getValueDouble() const {
     return __valueD;
 }
 
 const std::string&
 Expression::getValueString() const {
     return __valueS;
 }
 
 void
 Expression::setValue(const Atom<Identifier_t>&& v) {
     __valueS = v.get();
 }
 
 void Expression::setValueDouble(double value) {
     __valueD = value;
 }
 
 bool
 Expression::isValid() const {
     return (__state != INVALID);
 }
 
 bool
 Expression::isDefined() const {
     return (__state != BINDING && __state != INVALID);
 }
 
 Expression::Expression()
 : __state(INVALID), op(Operator::NONE), id(nextVacantId++) {
 }
 
 namespace details { namespace inconsistent {
 
 AST::AST() {
     Attachments::init<versions::VariableVersion>();
     Attachments::init<IdentifierSymbol>();
     Attachments::init<SymbolAlias>();
+    Attachments::init<TypeInferred>();
 }
 
 void
 AST::addInterfaceData(const ASTInterface& interface, Expression&& data) {
     __interfacesData.emplace(interface, move(data));
 }
 
 void
 AST::addDFAData(Expression &&data) {
     __dfadata.push_back(data);
 }
 
 void
 AST::addExternData(ExternData &&data) {
     __externdata.insert(__externdata.end(), data.entries.begin(), data.entries.end());
 }
 
 void
 AST::add(Function* f) {
     __functions.push_back(f);
     __indexFunctions.emplace(f->getName(), __functions.size() - 1);
 }
 
 void
 AST::add(MetaRuleAbstract *r) {
     __rules.push_back(r);
 }
 
 void
 AST::add(TypeAnnotation t, Atom<Identifier_t> alias) {
     if (t.__operator == TypeOperator::VARIANT) {
         for (int i = 0, size = t.fields.size(); i < size; ++i) {
             __dictVariants.emplace(t.fields[i], make_pair(t, i));
         }
     }
 
     __indexTypeAliases.emplace(alias.get(), move(t));
 }
 
 ManagedScpPtr
 AST::add(CodeScope* scope) {
     this->__scopes.push_back(scope);
     return ManagedScpPtr(this->__scopes.size() - 1, &this->__scopes);
 }
 
 std::string
 AST::getModuleName() {
     const std::string name = "moduleTest";
 
     return name;
 }
 
 ManagedPtr<Function>
 AST::findFunction(const std::string& name) {
     int count = __indexFunctions.count(name);
     if (!count) {
         return ManagedFnPtr::Invalid();
     }
 
     assert(count == 1);
 
     auto range = __indexFunctions.equal_range(name);
     return ManagedPtr<Function>(range.first->second, &this->__functions);
 }
 
 std::list<ManagedFnPtr>
 AST::getAllFunctions() const {
     const size_t size = __functions.size();
 
     std::list<ManagedFnPtr> result;
     for (size_t i = 0; i < size; ++i) {
         result.push_back(ManagedFnPtr(i, &this->__functions));
     }
 
     return result;
 }
 
 //TASK select default  specializations
 std::list<ManagedFnPtr>
 AST::getFunctionSpecializations(const std::string& fnName) const {
     auto functions = __indexFunctions.equal_range(fnName);
 
     std::list<ManagedFnPtr> result;
     std::transform(functions.first, functions.second, inserter(result, result.end()),
             [this](auto f) {
                 return ManagedFnPtr(f.second, &this->__functions);
             });
 
     return result;
 }
 
 template<>
 ManagedPtr<Function>
 AST::begin<Function>() {
     return ManagedPtr<Function>(0, &this->__functions);
 }
 
 template<>
 ManagedPtr<CodeScope>
 AST::begin<CodeScope>() {
     return ManagedPtr<CodeScope>(0, &this->__scopes);
 }
 
 template<>
 ManagedPtr<MetaRuleAbstract>
 AST::begin<MetaRuleAbstract>() {
     return ManagedPtr<MetaRuleAbstract>(0, &this->__rules);
 }
 
 void
 AST::recognizeVariantConstructor(Expression& function) {
     assert(function.op == Operator::CALL);
 
     std::string variant = function.getValueString();
     if (!__dictVariants.count(variant)) {
         return;
     }
 
     auto record = __dictVariants.at(variant);
     const TypeAnnotation& typ = record.first;
 
     function.op = Operator::VARIANT;
     function.setValueDouble(record.second);
     function.type = typ;
 }
 
 Atom<Number_t>
 AST::recognizeVariantConstructor(Atom<Identifier_t> ident) {
     std::string variant = ident.get();
     assert(__dictVariants.count(variant) && "Can't recognize variant constructor");
     auto record = __dictVariants.at(variant);
 
     return Atom<Number_t>(record.second);
 }
 
 void
 AST::postponeIdentifier(CodeScope* scope, const Expression& id) {
     bucketUnrecognizedIdentifiers.emplace(scope, id);
 }
 
 void
 AST::recognizePostponedIdentifiers() {
     for (const auto& identifier : bucketUnrecognizedIdentifiers) {
         if (!identifier.first->recognizeIdentifier(identifier.second)) {
             //exception: Ident not found
             std::cout << "Unknown symbol: " << identifier.second.getValueString() << std::endl;
             assert(false && "Symbol not found");
         }
     }
 }
 
 xreate::AST*
 AST::finalize() {
     //all finalization steps:
     recognizePostponedIdentifiers();
 
     return reinterpret_cast<xreate::AST*> (this);
 }
 
 } } //namespace details::incomplete
 
 Expanded<TypeAnnotation>
 AST::findType(const std::string& name) {
     // find in general scope:
     if (__indexTypeAliases.count(name))
         return expandType(__indexTypeAliases.at(name));
 
     //if type is unknown keep it as is.
     TypeAnnotation t(TypeOperator::CUSTOM,{});
     t.__valueCustom = name;
     return ExpandedType(move(t));
 }
 
 Expanded<TypeAnnotation>
 AST::expandType(const TypeAnnotation &t) const {
     return TypesResolver(this)(t);
 }
 
 ExpandedType
 AST::getType(const Expression& expression) {
     return typeinference::getType(expression, *this);
 }
 
 Function::Function(const Atom<Identifier_t>& name)
 : __entry(new CodeScope(0)) {
     __name = name.get();
 }
 
 void
 Function::addTag(Expression&& tag, const TagModifier mod) {
     string name = tag.getValueString();
     __tags.emplace(move(name), move(tag));
 }
 
 const std::map<std::string, Expression>&
 Function::getTags() const {
     return __tags;
 }
 
 CodeScope*
 Function::getEntryScope() const {
     return __entry;
 }
 
 void
 Function::addBinding(Atom <Identifier_t>&& name, Expression&& argument) {
     __entry->addBinding(move(name), move(argument));
 }
 
 const std::string&
 Function::getName() const {
     return __name;
 }
 
 ScopedSymbol
 CodeScope::registerIdentifier(const Expression& identifier) {
     versions::VariableVersion version = Attachments::get<versions::VariableVersion>(identifier, versions::VERSION_NONE);
 
     auto result = __identifiers.emplace(identifier.getValueString(), __vCounter);
     if (result.second) {
         ++__vCounter;
         return { __vCounter - 1, version };
     }
 
     return { result.first->second, version };
 }
 
 bool
 CodeScope::recognizeIdentifier(const Expression& identifier) const {
     versions::VariableVersion version = Attachments::get<versions::VariableVersion>(identifier, versions::VERSION_NONE);
     const std::string& name = identifier.getValueString();
 
     //search identifier in the current block
     if (__identifiers.count(name)) {
         VNameId id = __identifiers.at(name);
 
         Symbol s;
         s.identifier = ScopedSymbol{id, version};
         s.scope = const_cast<CodeScope*> (this);
         Attachments::put<IdentifierSymbol>(identifier, s);
 
         return true;
     }
 
     //search in the parent scope
     if (__parent) {
         return __parent->recognizeIdentifier(identifier);
     }
 
     return false;
 }
 
 ScopedSymbol
 CodeScope::getSymbol(const std::string& alias) {
     assert(__identifiers.count(alias));
     VNameId id = __identifiers.at(alias);
 
     return {id, versions::VERSION_NONE };
 }
 
 void
 CodeScope::addBinding(Expression&& var, Expression&& argument) {
     argument.__state = Expression::BINDING;
 
     __bindings.push_back(var.getValueString());
     ScopedSymbol binding = registerIdentifier(var);
     __declarations[binding] = move(argument);
 }
 
 Symbol
 CodeScope::addDefinition(Expression&& var, Expression&& body) {
     ScopedSymbol s = registerIdentifier(var);
     __declarations[s] = move(body);
 
     return Symbol{s, this};
 }
 
 CodeScope::CodeScope(CodeScope* parent)
 : __parent(parent) {
 }
 
 CodeScope::~CodeScope() {
 }
 
 void
 CodeScope::setBody(const Expression &body) {
     assert(__declarations.count(ScopedSymbol::RetSymbol)==0 && "Attempt to reassign scope body");
     __declarations[ScopedSymbol::RetSymbol] = body;
 }
 
-Expression&
-CodeScope::getBody() {
-    return __declarations[ScopedSymbol::RetSymbol];
+const Expression&
+CodeScope::getBody() const{
+    return __declarations.at(ScopedSymbol::RetSymbol);
 }
 
 const Expression&
 CodeScope::getDefinition(const Symbol& symbol, bool flagAllowUndefined){
-    CodeScope* self = symbol.scope;
+    const CodeScope* self = symbol.scope;
     return self->getDefinition(symbol.identifier, flagAllowUndefined);
 }
 
 const Expression&
 CodeScope::getDefinition(const ScopedSymbol& symbol, bool flagAllowUndefined) const{
     static Expression expressionInvalid;
 
     if (!__declarations.count(symbol)){
         if (flagAllowUndefined) return expressionInvalid;
         assert(false && "Symbol's declaration not found");
     }
 
     return __declarations.at(symbol);
 }
 
 void
 RuleArguments::add(const Atom<Identifier_t> &arg, DomainAnnotation typ) {
     emplace_back(arg.get(), typ);
 }
 
 void
 RuleGuards::add(Expression&& e) {
     push_back(e);
 }
 
 MetaRuleAbstract::
 MetaRuleAbstract(RuleArguments&& args, RuleGuards&& guards)
 : __args(std::move(args)), __guards(std::move(guards)) {
 }
 
 MetaRuleAbstract::~MetaRuleAbstract() {
 }
 
 RuleWarning::
 RuleWarning(RuleArguments&& args, RuleGuards&& guards, Expression&& condition, Atom<String_t>&& message)
 : MetaRuleAbstract(std::move(args), std::move(guards)), __message(message.get()), __condition(condition) {
 }
 
 RuleWarning::~RuleWarning() {
 }
 
 void
 RuleWarning::compile(ClaspLayer& layer) {
     //TODO restore addRuleWarning
     //layer.addRuleWarning(*this);
 }
 
 bool operator<(const ScopedSymbol& s1, const ScopedSymbol& s2) {
     return (s1.id < s2.id) || (s1.id == s2.id && s1.version < s2.version);
 }
 
 bool operator==(const ScopedSymbol& s1, const ScopedSymbol& s2) {
     return (s1.id == s2.id) && (s1.version == s2.version);
 }
 
 bool operator<(const Symbol& s1, const Symbol& s2) {
     return (s1.scope < s2.scope) || (s1.scope == s2.scope && s1.identifier < s2.identifier);
 }
 
 bool operator==(const Symbol& s1, const Symbol& s2) {
     return (s1.scope == s2.scope) && (s1.identifier == s2.identifier);
 }
 
 bool operator<(const Expression&a, const Expression&b) {
     if (a.__state != b.__state) return a.__state < b.__state;
     assert(a.__state != Expression::INVALID);
     switch (a.__state) {
         case Expression::IDENT:
         case Expression::STRING:
             return a.getValueString() < b.getValueString();
 
         case Expression::NUMBER:
             return a.getValueDouble() < b.getValueDouble();
 
         case Expression::COMPOUND:
         {
             assert(a.blocks.size() == 0);
             assert(b.blocks.size() == 0);
 
             if (a.op != b.op) {
                 return a.op < b.op;
             }
 
             bool flagAValid = ExpressionHints::isStringValueValid(a);
             bool flagBValid = ExpressionHints::isStringValueValid(b);
 
             if (flagAValid != flagBValid) {
                 return flagAValid < flagBValid;
             }
 
             if (flagAValid) {
                 if (a.getValueString() != b.getValueString()) {
                     return a.getValueString() < b.getValueString();
                 }
             }
 
             flagAValid = ExpressionHints::isDoubleValueValid(a);
             flagBValid = ExpressionHints::isDoubleValueValid(b);
 
             if (flagAValid != flagBValid) {
                 return flagAValid < flagBValid;
             }
 
             if (flagAValid) {
                 if (a.getValueDouble() != b.getValueDouble()) {
                     return a.getValueDouble() < b.getValueDouble();
                 }
             }
 
             if (a.operands.size() != b.operands.size()) {
                 return (a.operands.size() < b.operands.size());
             }
 
             for (size_t i = 0; i < a.operands.size(); ++i) {
                 bool result = a.operands[i] < b.operands[i];
                 if (result) return true;
             }
 
             return false;
         }
 
         case Expression::BINDING:
         case Expression::INVALID:
             assert(false);
     }
 
     return false;
 }
 
 bool
 Expression::operator==(const Expression& other) const {
     if (this->__state != other.__state) return false;
 
     if (ExpressionHints::isStringValueValid(*this)) {
         if (this->__valueS != other.__valueS) return false;
     }
 
     if (ExpressionHints::isDoubleValueValid(*this)) {
         if (this->__valueD != other.__valueD) return false;
     }
 
     if (this->__state != Expression::COMPOUND) {
         return true;
     }
 
     if (this->op != other.op) {
         return false;
     }
 
     if (this->operands.size() != other.operands.size()) {
         return false;
     }
 
     for (size_t i = 0; i<this->operands.size(); ++i) {
         if (!(this->operands[i] == other.operands[i])) return false;
     }
 
     assert(!this->blocks.size());
     assert(!other.blocks.size());
 
     return true;
 }
 
 const ScopedSymbol
 ScopedSymbol::RetSymbol = ScopedSymbol{0, versions::VERSION_NONE};
 
 } //end of namespace xreate
 
 
 
 
diff --git a/cpp/src/ast.h b/cpp/src/ast.h
index cea76a7..d52d052 100644
--- a/cpp/src/ast.h
+++ b/cpp/src/ast.h
@@ -1,727 +1,734 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * Author: pgess <v.melnychenko@xreate.org>
  * File: ast.h
  */ 
 
 #ifndef AST_H
 #define AST_H
 
 #include "attachments.h"
 
 #include <vector>
 #include <stdlib.h>
 #include <string>
 #include <list>
 #include <unordered_map>
 #include <unordered_set>
 #include <climits>
 #include "utils.h"
 #include <algorithm>
 
 namespace llvm {
     class Value;
 }
 
 namespace xreate {
     struct ScopedSymbol;
     struct Symbol;
 }
 
 namespace std {
     template<>
     struct hash<xreate::ScopedSymbol> {
         std::size_t operator()(xreate::ScopedSymbol const& s) const;
     };
 
     template<>
     struct equal_to<xreate::ScopedSymbol> {
         bool operator()(const xreate::ScopedSymbol& __x, const xreate::ScopedSymbol& __y) const;
     };
 
     template<>
     struct hash<xreate::Symbol> {
         size_t operator()(xreate::Symbol const& s) const;
     };
 
     template<>
     struct equal_to<xreate::Symbol> {
         bool operator()(const xreate::Symbol& __x, const xreate::Symbol& __y) const;
     };
 }
 
 namespace xreate {
 
 struct String_t {
 };
 
 struct Identifier_t {
 };
 
 struct Number_t {
 };
 
 struct Type_t {
 };
 
 template<typename A>
 class Atom {
 };
 
 //DEBT store line:col for all atoms/identifiers
 template<> class
 Atom<Identifier_t> {
 public:
     Atom(const std::wstring& value);
     Atom(std::string && name);
     const std::string& get() const;
 
 private:
     std::string __value;
 };
 
 template<>
 class Atom<Number_t> {
 public:
     Atom(wchar_t* value);
     Atom(int value);
     double get()const;
 
 private:
     double __value;
 };
 
 template<>
 class Atom<String_t> {
 public:
     Atom(const std::wstring& value);
     Atom(std::string && name);
     const std::string& get() const;
 
 private:
     std::string __value;
 };
 
 enum class TypePrimitive {
     Invalid, Bool, I8, I32, I64, Num, Int, Float, String
 };
 
 enum class TypeOperator {
     NONE, CALL, CUSTOM, VARIANT, ARRAY, STRUCT, ACCESS, LINK
 };
 
 struct llvm_array_tag {
 };
 
 struct struct_tag {
 };
 const llvm_array_tag tag_array = llvm_array_tag();
 const struct_tag tag_struct = struct_tag();
 
 /**
  * \brief Represents type to support type system
  * 
  * This class represents type in denormalized form, i.e. without arguments and aliases substitution
  * \sa AST::expandType()
  */
 class TypeAnnotation {
 public:
     TypeAnnotation();
     TypeAnnotation(const Atom<Type_t>& typ);
     TypeAnnotation(TypePrimitive typ);
     TypeAnnotation(llvm_array_tag, TypeAnnotation typ, int size);
 
     TypeAnnotation(TypeOperator op, std::initializer_list<TypeAnnotation> operands);
     TypeAnnotation(TypeOperator op, std::vector<TypeAnnotation>&& operands);
     void addBindings(std::vector<Atom<Identifier_t>>&& params);
     void addFields(std::vector<Atom<Identifier_t>>&& listFields);
     bool operator<(const TypeAnnotation& t) const;
     //   TypeAnnotation (struct_tag, std::initializer_list<TypePrimitive>);
 
     bool isValid() const;
 
     TypeOperator __operator = TypeOperator::NONE;
 
     std::vector<TypeAnnotation> __operands;
     TypePrimitive __value;
     std::string __valueCustom;
     int conjuctionId = -1; //conjunction point id (relevant for recursive types)
 
     uint64_t __size = 0;
     std::vector<std::string> fields;
     std::vector<std::string> bindings;
 private:
 };
 
 enum class Operator {
     ADD, SUB, MUL, DIV,
     EQU, NE, NEG, LSS,
     LSE, GTR, GTE, LIST,
     LIST_RANGE, LIST_NAMED,
     CALL, CALL_INTRINSIC, NONE,
     IMPL/* implication */, MAP,
     FOLD, FOLD_INF, LOOP_CONTEXT,
     INDEX, IF, SWITCH, SWITCH_ADHOC, SWITCH_VARIANT,
     CASE, CASE_DEFAULT, LOGIC_AND,
     ADHOC, CONTEXT_RULE, VARIANT
 };
 
 class Function;
 class AST;
 class CodeScope;
 class MetaRuleAbstract;
 
 typedef ManagedPtr<Function> ManagedFnPtr;
 typedef ManagedPtr<CodeScope> ManagedScpPtr;
 typedef ManagedPtr<MetaRuleAbstract> ManagedRulePtr;
 const ManagedScpPtr NO_SCOPE = ManagedScpPtr(UINT_MAX, 0);
 
 /**
  * \brief Represents every instruction in Xreate's syntax tree
  * \attention In case of any changes update xreate::ExpressionHints auxiliary helper as well
  * 
  * Expression is generic building block of syntax tree able to hold node data
  * as well as child nodes as operands. Not only instructions use expression for representation in syntax tree
  * but annotation as well. 
  * 
  * Additionally, `types` as a special kind of annotations use Expression-like data structure TypeAnnotation
  * \sa xreate::AST, xreate::TypeAnnotation
  */
 //
 struct Expression {
     friend class CodeScope;
     friend class ClaspLayer;
     friend class CFAPass;
     friend class ExpressionHints;
 
     Expression(const Operator &oprt, std::initializer_list<Expression> params);
     Expression(const Atom<Identifier_t>& ident);
     Expression(const Atom<Number_t>& number);
     Expression(const Atom<String_t>& a);
 
     Expression();
 
     void setOp(Operator oprt);
     void addArg(Expression&& arg);
     void addBindings(std::initializer_list<Atom<Identifier_t>> params);
     void bindType(TypeAnnotation t);
 
     template<class InputIt>
     void addBindings(InputIt paramsBegin, InputIt paramsEnd);
     void addTags(const std::list<Expression> tags) const;
     void addBlock(ManagedScpPtr scope);
 
     const std::vector<Expression>& getOperands() const;
     double getValueDouble() const;
     void setValueDouble(double value);
     const std::string& getValueString() const;
     void setValue(const Atom<Identifier_t>&& v);
     bool isValid() const;
     bool isDefined() const;
 
 
     bool operator==(const Expression& other) const;
 
     /**
      * \brief is it string, number, compound operation and so on
      */
     enum {
         INVALID, COMPOUND, IDENT, NUMBER, STRING, BINDING
     } __state = INVALID;
 
     /**
      * \brief Valid for compound State. Holds type of compound operator
      */
     Operator op;
     
     /**
      * \brief Unique id to identify expression within syntax tree
      */
     unsigned int id;
     
     /**
      * \brief Exact meaning depends on particular instruction
      * \details As an example, named lists/structs hold field names in bindings
      */
     std::vector<std::string> bindings;
     std::map<std::string, size_t> __indexBindings;
     
     /**
      * \brief Holds child instructions as arguments
      */
     std::vector<Expression> operands;
     
     /**
      * \brief Holds type of instruction's result
      */
     TypeAnnotation type;
 
     /**
      * \brief Holds additional annotations
      */
     mutable std::map<std::string, Expression> tags;
     
     /**
      * \brief Child code blocks
      * \details For example, If statement holds TRUE-branch as first and FALSE-branch as second block here
      */
     std::list<CodeScope*> blocks;
 
 private:
     std::string __valueS;
     double __valueD;
 
     static unsigned int nextVacantId;
 };
 
 bool operator<(const Expression&, const Expression&);
 
 template<class InputIt>
 void Expression::addBindings(InputIt paramsBegin, InputIt paramsEnd) {
     size_t index = bindings.size();
 
     std::transform(paramsBegin, paramsEnd, std::inserter(bindings, bindings.end()),
             [&index, this] (const Atom<Identifier_t> atom) {
                 std::string key = atom.get();
                 this->__indexBindings[key] = index++;
                 return key;
             });
 }
 
 typedef std::list<Expression> ExpressionList;
 
 enum class TagModifier {
     NONE, ASSERT, REQUIRE
 };
 
 enum class DomainAnnotation {
     FUNCTION, VARIABLE
 };
 
 class RuleArguments : public std::vector<std::pair<std::string, DomainAnnotation>>
 {
     public:
     void add(const Atom<Identifier_t>& name, DomainAnnotation typ);
 };
 
 class RuleGuards : public std::vector<Expression> {
 public:
     void add(Expression&& e);
 };
 
 
 class ClaspLayer;
 class LLVMLayer;
 
 class MetaRuleAbstract {
 public:
     MetaRuleAbstract(RuleArguments&& args, RuleGuards&& guards);
     virtual ~MetaRuleAbstract();
     virtual void compile(ClaspLayer& layer) = 0;
 protected:
     RuleArguments __args;
     RuleGuards __guards;
 };
 
 class RuleWarning : public MetaRuleAbstract {
     friend class ClaspLayer;
 public:
     RuleWarning(RuleArguments&& args, RuleGuards&& guards, Expression&& condition, Atom<String_t>&& message);
     virtual void compile(ClaspLayer& layer);
     ~RuleWarning();
 
 private:
     std::string __message;
     Expression __condition;
 };
 
 typedef unsigned int VNameId;
 
 namespace versions {
     typedef int VariableVersion;
     const VariableVersion VERSION_NONE = -2;
     const VariableVersion VERSION_INIT = 0;
 }
 
 template<>
 struct AttachmentsDict<versions::VariableVersion> {
     typedef versions::VariableVersion Data;
     static const unsigned int key = 6;
 };
 
 struct ScopedSymbol {
     VNameId id;
     versions::VariableVersion version;
 
     static const ScopedSymbol RetSymbol;
 };
 
 struct Symbol {
     ScopedSymbol identifier;
-    CodeScope * scope;
+    const CodeScope * scope;
 };
 
 struct IdentifierSymbol{};
 struct SymbolAlias{};
 
 template<>
 struct AttachmentsDict<IdentifierSymbol> {
     typedef Symbol Data;
     static const unsigned int key = 7;
 };
 
 template<>
 struct AttachmentsDict<SymbolAlias> {
     typedef Symbol Data;
     static const unsigned int key = 9;
 };
 
 typedef std::pair<Expression, TagModifier> Tag;
 
 bool operator<(const ScopedSymbol& s1, const ScopedSymbol& s2);
 bool operator==(const ScopedSymbol& s1, const ScopedSymbol& s2);
 bool operator<(const Symbol& s1, const Symbol& s2);
 bool operator==(const Symbol& s1, const Symbol& s2);
 
 /**
  * \brief Represents code block and single scope of visibility
  * 
  * Holds single expression as a *body* and set of variable assignments(declarations) used in body's expression
  * \sa xreate::AST
  */
 class CodeScope {
     friend class Function;
     friend class PassManager;
 
 public:
     CodeScope(CodeScope* parent = 0);
     ~CodeScope();
     
     /** \brief Set expression as a body */
     void setBody(const Expression& body);
     
     /** \brief Returns current code scope body */
-    Expression& getBody();
+    const Expression& getBody() const;
     
     /** \brief Adds variable definition to be used in body as well as in other declarations */
     Symbol addDefinition(Expression&& var, Expression&& body);
 
     /** \brief Returns symbols' definition */
     static const Expression& getDefinition(const Symbol& symbol, bool flagAllowUndefined = false);
     const Expression& getDefinition(const ScopedSymbol& symbol, bool flagAllowUndefined = false) const;
     
     /** \brief Adds variable defined elsewhere */
     void addBinding(Expression&& var, Expression&& argument);
     
     std::vector<std::string> __bindings;
     std::map<std::string, VNameId> __identifiers;
     CodeScope* __parent;
 
     //TODO move __definitions to SymbolsAttachments data
     //NOTE: definition of return type has  index 0 
     std::unordered_map<ScopedSymbol, Expression> __declarations;
     std::vector<Expression> tags;
     std::vector<Expression> contextRules;
     
 private:
     VNameId __vCounter = 1;
     ScopedSymbol registerIdentifier(const Expression& identifier);
 
 public:
     bool recognizeIdentifier(const Expression& identifier) const;
     ScopedSymbol getSymbol(const std::string& alias);
 };
 
 /**
  * \brief Represents single function in Xreate's syntax tree
  * 
  * Holds an entry code scope and `guardContext` required for function to operate
  * \sa xreate::AST
  */
 class Function {
     friend class Expression;
     friend class CodeScope;
     friend class AST;
 
 public:
     Function(const Atom<Identifier_t>& name);
 
     /**
      * \brief Adds function arguments
      */
     void addBinding(Atom <Identifier_t>&& name, Expression&& argument);
     
     /**
      * \brief Adds additional function annotations
      */
     void addTag(Expression&& tag, const TagModifier mod);
 
     const std::string& getName() const;
     const std::map<std::string, Expression>& getTags() const;
     CodeScope* getEntryScope() const;
     CodeScope* __entry;
     std::string __name;
     bool isPrefunction = false; //SECTIONTAG adhoc Function::isPrefunction flag
 
     Expression guardContext;
     Expression guard;
 private:
 
     std::map<std::string, Expression> __tags;
 };
 
 
 class ExternData;
 
 struct ExternEntry {
     std::string package;
     std::vector<std::string> headers;
 };
 
 typedef Expanded<TypeAnnotation> ExpandedType;
 
+struct TypeInferred{};
+template<>
+struct AttachmentsDict<TypeInferred> {
+    typedef ExpandedType Data;
+    static const unsigned int key = 11;
+};
+
 enum ASTInterface {
     CFA, DFA, Extern, Adhoc
 };
 
 struct FunctionSpecialization {
     std::string guard;
     size_t id;
 };
 
 struct FunctionSpecializationQuery {
     std::unordered_set<std::string> context;
 };
 
 template<>
 struct AttachmentsId<Expression>{
     static unsigned int getId(const Expression& expression){
         return expression.id;
     }
 };
 
 template<>
 struct AttachmentsId<Symbol>{
     static unsigned int getId(const Symbol& s){
         return s.scope->__declarations.at(s.identifier).id;
     }
 };
 
 template<>
 struct AttachmentsId<ManagedFnPtr>{
     static unsigned int getId(const ManagedFnPtr& f){
         const Symbol symbolFunction{ScopedSymbol::RetSymbol, f->getEntryScope()};
 
         return AttachmentsId<Symbol>::getId(symbolFunction);
     }
 };
 
 template<>
 struct AttachmentsId<unsigned int>{
     static unsigned int getId(const unsigned int id){
         return id;
     }
 };
 
 class TypesResolver;
 namespace details { namespace inconsistent {
     
     /**
      * \brief Syntax tree under construction in inconsistent form
      * 
      * Represents Syntax Tree under construction(**inconsistent state**). 
      * \attention Clients should use rather xreate::AST unless client's code explicitly works with Syntax Tree during construction. 
      * 
      * Typically instance only created by xreate::XreateManager and filled in by Parser
      * \sa xreate::XreateManager::prepare(std::string&&)
      */
 class AST {
     friend class xreate::TypesResolver;
 public:    
     AST();
     
     /**
      * \brief Adds new function to AST
      * \param f Function to register
      */
     void add(Function* f);
 
     /**
      * \brief Adds new declarative rule to AST
      * \param r Declarative Rule
      */
     void add(MetaRuleAbstract* r);
     
     /** \brief Registers new code block */
     ManagedScpPtr add(CodeScope* scope);
     
     /**
      * \brief Add new type to AST
      * @param t Type definition
      * @param alias Typer name
      */
     void add(TypeAnnotation t, Atom<Identifier_t> alias);
 
     /** \brief Current module's name */
     std::string getModuleName();
     
     /**
      * \brief Looks for function with given name
      * \param name Function name to find
      * \note Requires that only one function exists under given name
      * \return Found function
      */
     ManagedPtr<Function> findFunction(const std::string& name);
 
     /** \brief Returns all function in AST */
     std::list<ManagedFnPtr> getAllFunctions() const;
     
     /**
      * \brief Returns all specializations of a function with a given name
      * \param fnName function to find
      * \return list of found function specializations
      */
     std::list<ManagedFnPtr> getFunctionSpecializations(const std::string& fnName) const;
 
     /**
      * \return First element in Functions/Scopes/Rules list depending on template parameter
      * \tparam Target either Function or CodeScope or MetaRuleAbstract
      */
     template<class Target>
     ManagedPtr<Target> begin();
     
     /**
      * \brief Performs all necessary steps after AST is built
      * 
      * Performs all finzalisation steps and move AST into consistent state represented by xreate::AST
      * \sa xreate::AST
      * \return AST in consistent state
      */
     xreate::AST* finalize();
 
     typedef std::multimap<std::string, unsigned int> FUNCTIONS_REGISTRY;
     
     std::vector<ExternEntry> __externdata;
     std::list<Expression> __dfadata; //TODO move to more appropriate place
     std::list<std::string> __rawImports; //TODO move to more appropriate place
     std::multimap<ASTInterface, Expression> __interfacesData; //TODO CFA data here.
 
 private:
     std::vector<MetaRuleAbstract*> __rules;
     std::vector<Function*> __functions;
     std::vector<CodeScope*> __scopes;
 
     FUNCTIONS_REGISTRY __indexFunctions;
     
 protected:
     std::map<std::string, TypeAnnotation> __indexTypeAliases;
 
 public: 
     /**
      * \brief Stores DFA scheme for later use by DFA Pass
      * 
      *  Treats expression as a DFA scheme and feeds  to a DFA Pass later
      *  \paramn Expression DFA Scheme
      *  \sa xreate::DFAPass
      */
     void addDFAData(Expression&& data);
     
     /** \brief Stores data for later use by xreate::ExternLayer */
     void addExternData(ExternData&& data);
 
     /**
      * \brief Generalized function to store particular data for later use by particular pass
      * \param interface Particular Interface
      * \param data Particular data
      */
     void addInterfaceData(const ASTInterface& interface, Expression&& data);
     
 
                     /**\name Symbols Recognition */
 ///@{    
 public:
     //TODO revisit enums/variants, move to codescope
     /**
      * \brief Tries to find out whether expression is Variant constructor
      */
     void recognizeVariantConstructor(Expression& function);
     Atom<Number_t> recognizeVariantConstructor(Atom<Identifier_t> ident);
 
 private:
     std::map<std::string, std::pair<TypeAnnotation, int>> __dictVariants;
 
 public:
     std::set<std::pair<CodeScope*, Expression>> bucketUnrecognizedIdentifiers;
 
 public:
     /**
      * \brief Postpones unrecognized identifier for future second round of recognition
      * \param scope Code block identifier is encountered
      * \param id Identifier
      */
     void postponeIdentifier(CodeScope* scope, const Expression& id);
     
     /** \brief Second round of identifiers recognition done right after AST is fully constructed */
     void recognizePostponedIdentifiers();
 ///@}
 };
 
 template<>
 ManagedPtr<Function>
 AST::begin<Function>();
 
 template<>
 ManagedPtr<CodeScope>
 AST::begin<CodeScope>();
 
 template<>
 ManagedPtr<MetaRuleAbstract>
 AST::begin<MetaRuleAbstract>();
 
 } } // namespace details::incomplete
 
 /**
  * \brief Xreate's Syntax Tree in consistent state
  * 
  * Syntax Tree has two mutually exclusive possible states: 
  *  - inconsistent state while AST is under construction. Represented by xreate::details::inconsistent::AST
  *  - consistent state when AST is built and finalize() is done.
  * 
  * This class represents consistent state and should be used everywhere unless client's code explicitly works with AST under construction. 
  * Consistent AST enables access to additional functions(currently related to type management). 
  * \sa xreate::details::inconsistent::AST
  */
 class AST : public details::inconsistent::AST {
 public:
 
     AST() : details::inconsistent::AST() {}
     
     /**
      * \brief Computes fully expanded form of type by substituting all arguments and aliases 
      * \param t Type to expand
      * \return Expdanded or normal form of type
      * \sa TypeAnnotation
      */
     ExpandedType expandType(const TypeAnnotation &t) const;
     
     /**
      * Searches type by given name
      * \param name Typename to search
      * \return Expanded or normal form of desired type
      * \note if type name is not found  returns new undefined type with this name
      */
     ExpandedType findType(const std::string& name);
     
     /**
      * Invokes Type Inference Analysis to find out expanded(normal) form expressions's type
      * \sa typeinference.h
      * \param expression 
      * \return Type of expression
 
      */
     ExpandedType getType(const Expression& expression);
 };
 }
 #endif // AST_H
diff --git a/cpp/src/attachments.h b/cpp/src/attachments.h
index 40a6db7..2cbaf47 100644
--- a/cpp/src/attachments.h
+++ b/cpp/src/attachments.h
@@ -1,177 +1,178 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * Author: pgess <v.melnychenko@xreate.org>
  * File: attachments.h
  * Date: 3/15/15
  */ 
 
 #ifndef _XREATE_ATTACHMENTS_H_
 #define _XREATE_ATTACHMENTS_H_
 #include <unordered_map>
 #include <vector>
 #include <assert.h>
 #include <type_traits>
 
 namespace xreate
 {
         //Attachments dictionary
     template<class Tag>
     struct AttachmentsDict
     {
         // typedef void Data;
-        // static const unsigned int key (current unreserved - 11);
+        // static const unsigned int key (current unreserved - 12);
         //reserved attachments:
 //        1 containers::Implementation
 //        3 interpretation::InterpretationData
 //        5 interpretation::FunctionInterpretationData
 //        6 VariableVersion
 //        7 IdentifierSymbol
 //        8 versions::VersionImposedDependency
 //        9 SymbolAlias        
 //        10 CallGuard Expression
+//        11 TypeInferred
     };
     
     template<class Object>
     struct AttachmentsId{
         //static unsigned int getId(const Object& object);
     };
 
     
 template<class Data>
 class IAttachmentsContainer{
     protected:
         virtual bool  __exists(const unsigned int object)=0;
         virtual Data& __get(const unsigned int object)=0;
         virtual void  __put(const unsigned int object, Data data)=0;
 
     public:
         template<class Id>
         bool  exists(const Id& object){
             unsigned int id = AttachmentsId<Id>::getId(object);
 
             return __exists(id);
         }
 
         template<class Id>
         Data& get(const Id& object){
             unsigned int id = AttachmentsId<Id>::getId(object);
 
             return __get(id);
         }
 
         template<class Id>
         Data  get(const Id& object, const Data& dataDefault){
             unsigned int id = AttachmentsId<Id>::getId(object);
 
             if (! __exists(id)){
                 return dataDefault;
             }
 
             return __get(id);
         }
 
         template<class Id>
         void put(const Id& object, Data data){
             unsigned int id = AttachmentsId<Id>::getId(object);
 
                 __put(id, data);
         }
 
         virtual ~IAttachmentsContainer(){};
 };
     
 template<class Data>
 class AttachmentsContainerDefault: public IAttachmentsContainer<Data>{
 private:
     std::unordered_map<unsigned int, Data> __data;
 
     virtual bool  __exists(const unsigned int id){
         return __data.count(id);
     }
 
     virtual Data& __get(const unsigned int id){
         return __data.at(id);
     }
 
     virtual void __put(const unsigned int id, Data data){
         auto result = __data.emplace(id, data);
         assert(result.second);
     }
     
 public:    
     std::unordered_map<unsigned int, Data>& getRawStorage() {
         return __data;
     }
 };
 
 
 class Attachments{
     private:
         static std::vector<void*> __storage;
         
         template<class Tag>
         using  Data = typename AttachmentsDict<Tag>::Data;
         
     public:
         template<class Tag, class Id>
         static bool exists(const Id& object) {
             assert(AttachmentsDict<Tag>::key < __storage.size());
             assert(__storage.at(AttachmentsDict<Tag>::key));
             
             IAttachmentsContainer<Data<Tag>>* self = reinterpret_cast<IAttachmentsContainer<Data<Tag>>*>(__storage.at(AttachmentsDict<Tag>::key));
             return self->exists<Id>(object);
         }
         
         template<class Tag, class Id>
         static Data<Tag>& get(const Id& object){
             assert(AttachmentsDict<Tag>::key < __storage.size());
             assert(__storage.at(AttachmentsDict<Tag>::key));
             
             IAttachmentsContainer<Data<Tag>>* self = reinterpret_cast<IAttachmentsContainer<Data<Tag>>*>(__storage.at(AttachmentsDict<Tag>::key));
             return self->get<Id>(object);
         }
             
         template<class Tag, class Id>
         static Data<Tag>  get(const Id& object, const Data<Tag>& dataDefault){
             assert(AttachmentsDict<Tag>::key < __storage.size());
             assert(__storage.at(AttachmentsDict<Tag>::key));
             
             IAttachmentsContainer<Data<Tag>>* self = reinterpret_cast<IAttachmentsContainer<Data<Tag>>*>(__storage.at(AttachmentsDict<Tag>::key));
             return self->get<Id>(object, dataDefault);
         }
             
         template<class Tag, class Id>
         static void put(const Id& object, Data<Tag> data){
             assert(AttachmentsDict<Tag>::key < __storage.size());
             assert(__storage.at(AttachmentsDict<Tag>::key));
             
             IAttachmentsContainer<Data<Tag>>* self = reinterpret_cast<IAttachmentsContainer<Data<Tag>>*>(__storage.at(AttachmentsDict<Tag>::key));
             self->put<Id>(object, data);
         }
         
         template<class Tag>
         static void init(){
             unsigned int keyStorage = AttachmentsDict<Tag>::key;
             if (keyStorage+1 > __storage.size()){
                 __storage.resize(keyStorage + 1, nullptr);
             }
             
             __storage[keyStorage] = new AttachmentsContainerDefault<Data<Tag>>();
         }
         
         template<class Tag>
         static void init(IAttachmentsContainer<Data<Tag>>* container){
             unsigned int keyStorage = AttachmentsDict<Tag>::key;
             if (keyStorage+1 > __storage.size()){
                 __storage.resize(keyStorage + 1, nullptr);
             }
             
             __storage[keyStorage] = container;
         }
 };
 
 }
 
 #endif //_XREATE_ATTACHMENTS_H_
diff --git a/cpp/src/clasplayer.cpp b/cpp/src/clasplayer.cpp
index 5dc47e5..9cd4de8 100644
--- a/cpp/src/clasplayer.cpp
+++ b/cpp/src/clasplayer.cpp
@@ -1,382 +1,382 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * Author: pgess <v.melnychenko@xreate.org>
  * File: clasplayer.cpp
  */
 
 /**
  * \file    clasplayer.h
  * \brief   Resoner. Wrapper over Clasp reasoner library
  */
 
 #include "clasplayer.h"
 #include "analysis/aux.h"
 #include "utils.h"
 
 #include <gringo/scripts.hh>
 #include <boost/format.hpp>
 #include <boost/algorithm/string/join.hpp>
 #include <iostream>
 
 using namespace std;
 
 //TODO escape identifiers started with upper case symbol
 namespace xreate {
 
 void
 ClaspLayer::printWarnings(std::ostream& out)
 {
     const std::string warningTag = "warning";
 
     auto warningsRange = __model.equal_range(warningTag);
 
     for (auto warning=warningsRange.first; warning!= warningsRange.second; ++warning) {
         unsigned int warningId;
 
         Gringo::Symbol params;
         std::tie(warningId, params) = parse<unsigned int, Gringo::Symbol>(warning->second);
 
         cout << "Warning: " << __warnings.at(warningId) << " ";
         params.print(out);
         out<<params;
     }
 }
 
 bool
 ClaspLayer::handleSolution(Gringo::Model const &model) {
     std::list<std::string> warnings;
     cout << "Model: " << endl;
 
     const string& atomBindVar = Config::get("clasp.bindings.variable");
     const string& atomBindFunc = Config::get("clasp.bindings.function");
     const string& atomBindScope = Config::get("clasp.bindings.scope");
 
     for (Gringo::Symbol atom : model.atoms(clingo_show_type_atoms)) {
         atom.print(cout);
         cout <<" | "<< endl;
 
         string atomName(atom.name().c_str());
         if (atomName == atomBindVar || atomName == atomBindFunc || atomName == atomBindScope){
             string name = std::get<1>(parse<Gringo::Symbol, Gringo::Symbol>(atom)).name().c_str();
             __model.emplace(move(name), move(atom));
         }
 
         __model.emplace(atomName, move(atom));
     }
 
     return true;
 }
 
 void
 ClaspLayer::registerReport(IAnalysisReport* report){
     __reports.push_back(report);
 }
 
 void
 ClaspLayer::runReports(){
     for(IAnalysisReport* report: __reports){
         report->print(__partGeneral);
         delete report;
     }
 
     __reports.clear();
 }
 
 void
 ClaspLayer::addRuleWarning(const RuleWarning &rule) {
     //__partGeneral << rule << endl;
 
     list<string> domains;
     boost::format formatDef("%1%(%2%)");
     std::transform(rule.__args.begin(), rule.__args.end(), std::inserter(domains, domains.begin()),
             [&formatDef](const std::pair<std::string, DomainAnnotation> &argument) {
                 string domain;
                 switch (argument.second) {
                     case DomainAnnotation::FUNCTION:
                         domain = "function";
                         break;
                     case DomainAnnotation::VARIABLE:
                         domain = "variable";
                         break;
                 }
 
                 return boost::str(formatDef % domain % argument.first);
             });
 
     list<string> vars;
     std::transform(rule.__args.begin(), rule.__args.end(), std::inserter(vars, vars.begin()),
             [](const std::pair<std::string, DomainAnnotation> &argument) {
                 return argument.first.c_str();
             });
 
     list<list<string>> guardsRaw;
     std::transform(rule.__guards.begin(), rule.__guards.end(), std::inserter(guardsRaw, guardsRaw.begin()),
             [this](const Expression &guard) {
                 return xreate::analysis::compile(guard);
             });
 
     const list<string>& guards = xreate::analysis::multiplyLists(std::move(guardsRaw));
     list<string> &&branches = xreate::analysis::compileNeg(rule.__condition);
 
     boost::format formatWarning("warning(%1%, (%2%)):- %3%, %4%, %5%.");
     for (const string &guardsJoined: guards)
         for (const string &branch: branches) {
             unsigned int hook = registerWarning(string(rule.__message));
 
             __partGeneral  <<  formatWarning
                     %(hook)
                     %(boost::algorithm::join(vars, ", "))
                     %(branch)
                     %(guardsJoined)
                     %(boost::algorithm::join(domains, ", "))
                 <<endl;
         }
 }
 
 
 
 unsigned int
 ClaspLayer::registerWarning(std::string &&message) {
     static int warningId = 0;
     __warnings.emplace(warningId, message);
     return warningId++;;
 }
 
 void
 ClaspLayer::involveImports()    {
     ostream &out = __partGeneral;
 
     for (string fn: ast->__rawImports)
     {
         std::ifstream file(fn);
         if (!file) continue;
 
         while(!file.eof()){
             string line;
             std::getline(file, line);
             out << line << endl;
         }
     }
 }
 
 void
 ClaspLayer::addRawScript(std::string&& script){
     __partGeneral << script;
 }
 
 void
 ClaspLayer::run() {
     involveImports();
     runReports();
 
     ostringstream program;
     program << __partTags.str() << __partGeneral.str();
     cout << FYEL(program.str()) << endl;
 
     std::vector<char const *> args{"clingo", nullptr};
     DefaultGringoModule moduleDefault;
     Gringo::Scripts scriptsDefault(moduleDefault);
     ClingoLib ctl(scriptsDefault, 0, args.data(), {}, 0);
 
     ctl.add("base", {}, program.str());
     ctl.ground({{"base", {}}}, nullptr);
 
 //          solve
     Gringo::SolveResult result = ctl.solve([this](Gringo::Model const &model) {
         this->handleSolution(model);
         return true;
     }, {});
 
     if (result.satisfiable() == Gringo::SolveResult::Satisfiable) {
         cout << FGRN("SUCCESSFULLY") << endl;
     } else {
         cout << FRED("UNSUCCESSFULLY") << endl;
     }
 
 //      invoke all query plugins to process clasp data
     for (auto q: __queries)
     {
         q.second->init(this);
     }
 }
 
 ClaspLayer::ClaspLayer() {
 }
 
 ClaspLayer::ModelFragment
 ClaspLayer::query(const std::string& atom)
 {
     if (! __model.count(atom)){
         return boost::none;
     }
 
     return ModelFragment(__model.equal_range(atom));
 }
 
 ScopePacked
-ClaspLayer::pack(CodeScope* const scope) {
+ClaspLayer::pack(const CodeScope* const scope) {
     auto pos = __indexScopes.emplace(scope, __indexScopes.size());
     if (pos.second)
-            __registryScopes.push_back(scope);
+        __registryScopes.push_back(scope);
 
     return pos.first->second;
 }
 
 size_t
 ClaspLayer::getScopesCount() const{
     return __registryScopes.size();
 }
 
 SymbolPacked
 ClaspLayer::pack(const Symbol& symbol, std::string hintSymbolName)
 {
     SymbolPacked result(symbol.identifier.id, symbol.identifier.version, pack(symbol.scope));
     __indexSymbolNameHints.emplace(result, hintSymbolName);
 
     return result;
 }
 
 Symbol
 ClaspLayer::unpack(const SymbolPacked& symbol)
 {
     return Symbol{ScopedSymbol{symbol.identifier, symbol.version}, __registryScopes[symbol.scope]};
 };
 
 std::string
 ClaspLayer::getHintForPackedSymbol(const SymbolPacked& symbol){
     auto result = __indexSymbolNameHints.find(symbol);
     return (result == __indexSymbolNameHints.end())? "" : result->second;
 }
 
 bool operator==(const SymbolPacked& s1, const SymbolPacked& s2)
 {
     return s1.identifier == s2.identifier && s1.scope == s2.scope;
 }
 
 bool operator<(const SymbolPacked& s1, const SymbolPacked& s2)
 {
     return  s1.scope < s2.scope  || (s1.scope ==  s2.scope && s1.identifier < s2.identifier);
 }
 
 IQuery*
 ClaspLayer::registerQuery(IQuery *query, const QueryId& id) {
     return __queries.emplace(id, query).first->second;
 }
 
 IQuery*
 ClaspLayer::getQuery(const QueryId& id){
     assert(__queries.count(id) && "Undefined query");
     return __queries.at(id);
 }
 
 Expression
 ParseImplAtom<Expression>::get(const Gringo::Symbol& atom) {
     switch (atom.type()) {
         case Gringo::SymbolType::Num: return Expression(atom.num());
         case Gringo::SymbolType::Str: return Expression(Atom<String_t>(std::string(atom.string().c_str())));
 
         case Gringo::SymbolType::Fun:
         {
             //FUNC
             Expression result(Operator::CALL,{Expression(Atom<Identifier_t>(std::string(atom.name().c_str())))});
             for (const Gringo::Symbol& arg : atom.args()) {
                 result.addArg(ParseImplAtom<Expression>::get(arg));
             }
 
             return result;
         }
 
         default:
         {
             assert(false);
         }
     }
 }
 
 int
 ParseImplAtom<int>::get(const Gringo::Symbol& atom) {
     switch (atom.type()){
         case Gringo::SymbolType::Num: return atom.num();
         default: break;
     }
 
     assert(false && "Inappropriate symbol type");
 }
 
 std::string
 ParseImplAtom<std::string>::get(const Gringo::Symbol& atom) {
     switch (atom.type()) {
         case Gringo::SymbolType::Str: return atom.string().c_str();
         case Gringo::SymbolType::Fun: return atom.name().c_str();
 
         default: break;
     }
 
     assert(false && "Inappropriate symbol type");
 }
 
 SymbolPacked
 ParseImplAtom<SymbolPacked>::get(const Gringo::Symbol& atom) {
     auto result = ClaspLayer::parse<unsigned int, unsigned int, unsigned int>(atom);
     return SymbolPacked(std::get<0>(result), std::get<1>(result), std::get<2>(result));
 };
 
 Gringo::Symbol
 ParseImplAtom<Gringo::Symbol>::get(const Gringo::Symbol& atom) {
     return atom;
 }
 
 std::list<Gringo::Symbol>
 ParseImplAtom<std::list<Gringo::Symbol>>::get(const Gringo::Symbol& atom){
     assert (atom.type() == Gringo::SymbolType::Fun);
     std::list<Gringo::Symbol> result;
 
     for (const Gringo::Symbol& arg: atom.args()) {
         result.push_back(ParseImplAtom<Gringo::Symbol>::get(arg));
     }
 
     return result;
 }
 
 } //end of xreate namespace
 
 /**
  * \class xreate::ClaspLayer
  * \brief Reasoning and logic Solver.
  *
  * Wraps external brilliant fantastic tool [Clasp solver](https://potassco.org/clasp/)
  *
  * For building *logic program* for reasoning ClaspLayer takes input from:
  *  - Raw scripts. Client could append arbitrary ASP script to _logic program_. \ref addRawScript()
  *  - Includes. There is possibility to specify external files with ASP scripts
  *    to append to _logic program_. \ref involveImports() (private member)
  *  - Diagnostic rules. Rules that produce diagnostic messages during
  *    compilation(warnings) or even able to halt compilation with errors.
  *    addRuleWarning(), \ref registerWarning()
  *  - DFA data. \ref setDFAData()
  *  - CFA data. \ref setCFAData()
  *  - Dominators Analysis. See xreate::dominators::DominatorsTreeAnalysisProvider.
  *    Executed by \ref run()
  *  - Context rules. See xreate::ContextRule and general [Context Explanation](/w/concepts/context)
  *
  * Data sources implement xreate::IAnalysisReport. Generally, input could be loosely divided into three categories:
  *  - *Internally derived* data. CFA, DFA, Dominators analyses *automatically* feed reasoner by
  *     useful  insights about data, structure and algorithms of a program
  *  - *User provided* data. CFA, DFA, Diagnostic/Context rules feed reasoner by
  *      annotations Developer specifically  provides manually
  *  - *External* data. Raw scripts and includes feed reasoner with third-party data
  *    related to a different aspects of a program possibly produced by external analyzers
  *
  * Once ClaspLayer got input from all providers and logic program is fully constructed
  * it runs external Clasp solver and receives back desired solutions.
  *
  * Output of Clasp reasoner is recognized and accessed via *queries*.
  * IQuery represents an interface between reasoner's output and rest of Xreate.
  * Each query inherits xreate::IQuery interface. Currently there are queries as follows:
  *  - xreate::containers::Query to catch solutions regarding Containers implementation. See [Containers Explanation](/w/concepts/containers)
  *  - xreate::context::ContextQuery to catch solution regarding Context. See [Context Explanation](/w/concepts/context)
  *
  * \sa See xreate::dfa::DFAPass, xreate::cfa::CFAPass, xreate::IQuery, xreate::IAnalysisReport, xreate::dominators::DominatorsTreeAnalysisProvider
  */
\ No newline at end of file
diff --git a/cpp/src/clasplayer.h b/cpp/src/clasplayer.h
index f2c097f..2e4157a 100644
--- a/cpp/src/clasplayer.h
+++ b/cpp/src/clasplayer.h
@@ -1,229 +1,229 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * Author: pgess <v.melnychenko@xreate.org>
  * File: clasplayer.h
  */ 
 
 #ifndef CLASPLAYER_H
 #define CLASPLAYER_H
 
 #include "ast.h"
 #include "contextrule.h"
 
 #include <clingo/clingocontrol.hh>
 #include <string>
 #include <climits>
 #include <boost/bimap.hpp>
 #include <boost/bimap/multiset_of.hpp>
 #include <boost/optional.hpp>
 #include <boost/scoped_ptr.hpp>
 #include <list>
 
 namespace xreate {
 
 typedef unsigned int ScopePacked;
 
 struct SymbolPacked {
     SymbolPacked(){}
     SymbolPacked(ScopedSymbol i, ScopePacked s): identifier(i.id), version(i.version), scope(s){}
     SymbolPacked(VNameId symbolId, versions::VariableVersion symbolVersion, ScopePacked symbolScope)
         : identifier(symbolId), version(symbolVersion), scope(symbolScope){}
     
     VNameId identifier;
     versions::VariableVersion version;
     ScopePacked scope;
 };
 
 bool operator==(const SymbolPacked& s1, const SymbolPacked& s2);
 bool operator<(const SymbolPacked& s1, const SymbolPacked& s2);
 
 enum class DFGConnection {
     STRONG, WEAK, PROTOTYPE
 };
 
 /** \brief Designated to mark analysis results that can be composed as *logic program* */
 class IAnalysisReport {
 public:
     /** \brief Composes *logic program* based on analysis data into ASP format and appends to a stream*/
     virtual void print(std::ostringstream& output) const = 0;
     virtual ~IAnalysisReport(){};
 };
 
 /** \brief Logic program query interface */
 class IQuery {
 public:
     virtual void init(ClaspLayer* clasp) = 0;
     virtual ~IQuery() {}
 };
 
 enum class QueryId {
     ContainersQuery,
     ContextQuery,
     PtrvalidQuery,
     PolymorphQuery
 };
 
 namespace dfa{
     class DFAGraph;
 }
 
 namespace cfa {
     class CFAGraph;
 }
 
 class ClaspLayer {
     friend class ContextRule;
 
                     /**\name Data Providers Management */
 ///@{
 public:   
     void registerReport(IAnalysisReport* report);
     void runReports();
     
     /** \brief Appends arbitrary string to *logic program* 
      */
     void addRawScript(std::string&& script);
 
 private: 
     std::list<IAnalysisReport*> __reports;
     
     /** Includes external text files to a *logic program* */    
     void involveImports();
 ///@}                
 
                     /**\name Queries Management */
 ///@{    
 public:
     /** \brief Adds query. See xreate::IQuery  */
     IQuery* registerQuery(IQuery* query, const QueryId& id);
     
     /** \brief Returns particular query. See xreate::IQuery */
     IQuery* getQuery(const QueryId& id);
 
     template<class ...Types>
     static std::tuple<Types...> parse(const Gringo::Symbol& atom);
 
     typedef std::multimap<std::string, Gringo::Symbol>::const_iterator ModelIterator;
     typedef boost::optional<std::pair<ClaspLayer::ModelIterator, ClaspLayer::ModelIterator>> ModelFragment;
     ModelFragment query(const std::string& atom);
 
     size_t getScopesCount() const;
     SymbolPacked pack(const Symbol& symbol, std::string hintSymbolName = "");
-    ScopePacked pack(CodeScope * const scope);
+    ScopePacked pack(const CodeScope * const scope);
     Symbol unpack(const SymbolPacked& symbol);
     std::string getHintForPackedSymbol(const SymbolPacked& symbol);
 ///@}
     
 private:
     std::map<QueryId, IQuery*> __queries;
     std::multimap<std::string, Gringo::Symbol> __model;
     std::map<SymbolPacked, std::string> __indexSymbolNameHints;
     std::unordered_map<const CodeScope*, unsigned int> __indexScopes;
-    std::vector<CodeScope*> __registryScopes;
+    std::vector<const CodeScope*> __registryScopes;
 
                     /**\name Diagnostic */    
 ///@{
 //TODO diagnostic move over to separate provider/query 
 public:
     /** \brief Adds diagnostic rule  */
     void addRuleWarning(const RuleWarning &rule);
     
     /** \brief Registers diagnostic messages  */
     unsigned int registerWarning(std::string &&message);
 
 private:
     std::map<unsigned int, std::string> __warnings;
     void printWarnings(std::ostream& out);
 ///@}
     
 ///@{
 public:
     ClaspLayer();
     
     /** \brief Executes reasoning */
     void run();
 ///@}
     AST *ast;
     
 private:
     
     std::ostringstream __partTags;
     std::ostringstream __partGeneral;
 
     bool handleSolution(Gringo::Model const &model);
 };
 
 template<class typ>
 struct ParseImplAtom {
 
     static typ get(const Gringo::Symbol& atom) {
         return atom.num();
     }
 };
 
 template<>
 struct ParseImplAtom<int> {
     static int get(const Gringo::Symbol& atom);
 };
 
 template<>
 struct ParseImplAtom<std::string> {
     static std::string get(const Gringo::Symbol& atom);
 };
 
 template<>
 struct ParseImplAtom<SymbolPacked> {
     static SymbolPacked get(const Gringo::Symbol& atom);
 };
 
 template<>
 struct ParseImplAtom<Gringo::Symbol> {
     static Gringo::Symbol get(const Gringo::Symbol& atom);
 };
 
 template<>
 struct ParseImplAtom<std::list<Gringo::Symbol>>{
     static std::list<Gringo::Symbol> get(const Gringo::Symbol& atom);
 };
 
 template<>
 struct ParseImplAtom<Expression> {
     static Expression get(const Gringo::Symbol& atom);
 };
 
 template<class Tuple, size_t index>
 struct Parse_Impl {
 
     static void parse(Tuple& tup, Gringo::SymSpan::iterator arg) {
         const size_t tupleSize = std::tuple_size<Tuple>::value;
         typedef typename std::tuple_element < tupleSize - index, Tuple>::type ElType;
 
         ElType& el = std::get < tupleSize - index > (tup);
 
         Gringo::Symbol atom = *arg;
         el = ParseImplAtom<ElType>::get(atom);
 
         Parse_Impl<Tuple, index - 1 > ::parse(tup, ++arg);
     }
 };
 
 template<class Tuple>
 struct Parse_Impl<Tuple, 0> {
 
     static void parse(Tuple& tup, Gringo::SymSpan::iterator arg) {
     }
 };
 
 template<class ...Types>
 std::tuple<Types...>
 ClaspLayer::parse(const Gringo::Symbol& atom) {
     typedef std::tuple < Types...> Tuple;
     Tuple tup;
     Parse_Impl<Tuple, std::tuple_size<Tuple>::value>::parse(tup, atom.args().first);
 
     return tup;
 }
 } //end of xreate namespace
 #endif
diff --git a/cpp/src/compilation/advanced.cpp b/cpp/src/compilation/advancedinstructions.cpp
similarity index 78%
rename from cpp/src/compilation/advanced.cpp
rename to cpp/src/compilation/advancedinstructions.cpp
index 04db2cf..8c51228 100644
--- a/cpp/src/compilation/advanced.cpp
+++ b/cpp/src/compilation/advancedinstructions.cpp
@@ -1,390 +1,445 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * File:   InstructionsAdvanced.cpp
  * Author: pgess <v.melnychenko@xreate.org>
  *
  * Created on June 26, 2016, 6:00 PM
  */
 
 /**
  * \file    advanced.h
  * \brief   Compilation of statements that require more than one LLVM instruction
  */
 
-#include "compilation/advanced.h"
+#include "compilation/advancedinstructions.h"
 #include "compilation/containers.h"
 #include "compilation/transformersaturation.h"
 
 #include "query/context.h"
 #include "query/containers.h"
 #include "llvmlayer.h"
 #include "ast.h"
 
 using namespace std;
 using namespace llvm;
 using namespace xreate;
 using namespace xreate::containers;
 using namespace xreate::compilation;
 
 #define NAME(x) (hintRetVar.empty()? x : hintRetVar)
 #define UNUSED(x) (void)(x)
 #define EXPAND_CONTEXT         \
     LLVMLayer* llvm = context.pass->man->llvm; \
     compilation::ICodeScopeUnit* scope = context.scope; \
     compilation::IFunctionUnit* function = context.function;
 
-Advanced::Advanced(compilation::Context ctx)
+AdvancedInstructions::AdvancedInstructions(compilation::Context ctx)
 : context(ctx), tyNum(static_cast<llvm::IntegerType*> (ctx.pass->man->llvm->toLLVMType(ExpandedType(TypeAnnotation(TypePrimitive::Num))))) {
 }
 
 llvm::Value*
-Advanced::compileMapSolidOutput(const Expression &expr, const std::string hintRetVar) {
+AdvancedInstructions::compileMapSolidOutput(const Expression &expr, const std::string hintRetVar) {
     EXPAND_CONTEXT
     UNUSED(scope);
 
     //initialization
     Symbol symbolIn = Attachments::get<IdentifierSymbol>(expr.getOperands()[0]);
 
     ImplementationRec<SOLID> implIn = containers::Query::queryImplementation(symbolIn).extract<SOLID>(); // impl of input list
     size_t size = implIn.size;
     CodeScope* scopeLoop = expr.blocks.front();
     std::string varEl = scopeLoop->__bindings[0];
 
     Iterator* it = Iterator::create(context, symbolIn);
     llvm::Value *rangeFrom = it->begin();
     llvm::Value *rangeTo = it->end();
 
     //definitions
     ArrayType* tyNumArray = (ArrayType*) (llvm->toLLVMType(ExpandedType(TypeAnnotation(tag_array, TypePrimitive::Num, size))));
     llvm::IRBuilder<> &builder = llvm->builder;
 
     llvm::BasicBlock *blockLoop = llvm::BasicBlock::Create(llvm::getGlobalContext(), "loop", function->raw);
     llvm::BasicBlock *blockBeforeLoop = builder.GetInsertBlock();
     llvm::BasicBlock *blockAfterLoop = llvm::BasicBlock::Create(llvm::getGlobalContext(), "postloop", function->raw);
     Value* dataOut = llvm->builder.CreateAlloca(tyNumArray, ConstantInt::get(tyNum, size), NAME("map"));
 
     // * initial check
     Value* condBefore = builder.CreateICmpSLE(rangeFrom, rangeTo);
     builder.CreateCondBr(condBefore, blockLoop, blockAfterLoop);
 
     // create PHI:
     builder.SetInsertPoint(blockLoop);
     llvm::PHINode *stateLoop = builder.CreatePHI(tyNum, 2, "mapIt");
     stateLoop->addIncoming(rangeFrom, blockBeforeLoop);
 
     // loop body:
     Value* elIn = it->get(stateLoop, varEl);
     compilation::ICodeScopeUnit* scopeLoopUnit = function->getScopeUnit(scopeLoop);
     scopeLoopUnit->bindArg(elIn, move(varEl));
     Value* elOut = scopeLoopUnit->compile();
     Value *pElOut = builder.CreateGEP(dataOut, ArrayRef<Value *>(std::vector<Value*>{ConstantInt::get(tyNum, 0), stateLoop}));
     builder.CreateStore(elOut, pElOut);
 
     //next iteration preparing
     Value *stateLoopNext = builder.CreateAdd(stateLoop, llvm::ConstantInt::get(tyNum, 1));
     stateLoop->addIncoming(stateLoopNext, builder.GetInsertBlock());
 
     //next iteration checks:
     Value* condAfter = builder.CreateICmpSLE(stateLoopNext, rangeTo);
     builder.CreateCondBr(condAfter, blockLoop, blockAfterLoop);
 
     //finalization:
     builder.SetInsertPoint(blockAfterLoop);
 
     return dataOut;
 }
 
 Value*
-Advanced::compileArrayIndex(llvm::Value* aggregate, std::vector<llvm::Value *> indexes, std::string hintRetVar) {
+AdvancedInstructions::compileArrayIndex(llvm::Value* aggregate, std::vector<llvm::Value *> indexes, std::string hintRetVar) {
     EXPAND_CONTEXT
     UNUSED(function);
     UNUSED(scope);
 
     indexes.insert(indexes.begin(), llvm::ConstantInt::get(tyNum, 0));
     llvm::Value *pEl = llvm->builder.CreateGEP(aggregate, llvm::ArrayRef<llvm::Value *>(indexes));
     return llvm->builder.CreateLoad(pEl, NAME("el"));
 }
 
 Value*
-Advanced::compileStructIndex(llvm::Value* aggregate, const ExpandedType& t, const std::string& idx) {
+AdvancedInstructions::compileStructIndex(llvm::Value* aggregate, const ExpandedType& t, const std::string& idx) {
     EXPAND_CONTEXT
     UNUSED(scope);
     UNUSED(function);
     TypeUtils types(llvm);
     std::vector<std::string>&& fields = types.getStructFields(t);
 
     for (unsigned i = 0, size = fields.size(); i < size; ++i) {
         if (fields.at(i) == idx) {
             //dereference pointer
             if (types.isPointer(t)) {
                 llvm::Value* addr = llvm->builder.CreateConstGEP2_32(nullptr, aggregate, 0, i);
                 return llvm->builder.CreateLoad(addr);
             }
 
             return llvm->builder.CreateExtractValue(aggregate, llvm::ArrayRef<unsigned>{i});
         }
     }
 
     assert(false && "not found required struct field");
     return nullptr;
 }
 
 llvm::Value*
-Advanced::compileFold(const Expression& fold, const std::string& hintRetVar) {
+AdvancedInstructions::compileFold(const Expression& fold, const std::string& hintRetVar) {
     EXPAND_CONTEXT
     assert(fold.op == Operator::FOLD);
 
     //initialization:
     Symbol varInSymbol = Attachments::get<IdentifierSymbol>(fold.getOperands()[0]);
     Implementation info = Query::queryImplementation(varInSymbol);
 
     Iterator* it = Iterator::create(context, varInSymbol);
     llvm::Value* rangeBegin = it->begin();
     llvm::Value* rangeEnd = it->end();
     llvm::Value* accumInit = scope->process(fold.getOperands()[1]);
     std::string varIn = fold.getOperands()[0].getValueString();
     std::string varAccum = fold.bindings[1];
     std::string varEl = fold.bindings[0];
 
     llvm::BasicBlock *blockBeforeLoop = llvm->builder.GetInsertBlock();
     std::unique_ptr<TransformerSaturation> transformerSaturation(new TransformerSaturation(blockBeforeLoop, context.pass->managerTransformations));
 
 
     llvm::BasicBlock *blockLoop = llvm::BasicBlock::Create(llvm::getGlobalContext(), "fold", function->raw);
     llvm::BasicBlock *blockLoopBody = llvm::BasicBlock::Create(llvm::getGlobalContext(), "fold_body", function->raw);
     llvm::BasicBlock *blockAfterLoop = llvm::BasicBlock::Create(llvm::getGlobalContext(), "fold_after", function->raw);
     llvm::BasicBlock *blockNext = llvm::BasicBlock::Create(llvm::getGlobalContext(), "fold_next", function->raw);
 
     llvm->builder.CreateBr(blockLoop);
 
     // * create phi
     llvm->builder.SetInsertPoint(blockLoop);
     llvm::PHINode *accum = llvm->builder.CreatePHI(accumInit->getType(), 2, varAccum);
     accum->addIncoming(accumInit, blockBeforeLoop);
     llvm::PHINode *itLoop = llvm->builder.CreatePHI(rangeBegin->getType(), 2, "foldIt");
     itLoop->addIncoming(rangeBegin, blockBeforeLoop);
 
     // * loop checks
     Value* condRange = llvm->builder.CreateICmpNE(itLoop, rangeEnd);
     llvm->builder.CreateCondBr(condRange, blockLoopBody, blockAfterLoop);
 
     // * loop body
     llvm->builder.SetInsertPoint(blockLoopBody);
     CodeScope* scopeLoop = fold.blocks.front();
     compilation::ICodeScopeUnit* loopUnit = function->getScopeUnit(scopeLoop);
     Value* elIn = it->get(itLoop);
     loopUnit->bindArg(accum, move(varAccum));
     loopUnit->bindArg(elIn, move(varEl));
     Value* accumNext = loopUnit->compile();
 
     // * Loop saturation checks
     bool flagSaturationTriggered = transformerSaturation->insertSaturationChecks(blockNext, blockAfterLoop, context);
     llvm::BasicBlock* blockSaturation = llvm->builder.GetInsertBlock();
     if (!flagSaturationTriggered){
         llvm->builder.CreateBr(blockNext);
     }
 
     // * computing next iteration state
     llvm->builder.SetInsertPoint(blockNext);
     Value *itLoopNext = it->advance(itLoop);
     accum->addIncoming(accumNext, llvm->builder.GetInsertBlock());
     itLoop->addIncoming(itLoopNext, llvm->builder.GetInsertBlock());
     llvm->builder.CreateBr(blockLoop);
 
     // * finalization:
     llvm->builder.SetInsertPoint(blockAfterLoop);
     if (!flagSaturationTriggered){
         return accum;
     }
 
     llvm::PHINode* result = llvm->builder.CreatePHI(accumInit->getType(), 2);
     result->addIncoming(accum, blockLoop);
     result->addIncoming(accumNext, blockSaturation);
     return result;
 }
 
 llvm::Value*
-Advanced::compileFoldInf(const Expression& fold, const std::string& hintRetVar) {
+AdvancedInstructions::compileFoldInf(const Expression& fold, const std::string& hintRetVar) {
     EXPAND_CONTEXT
     assert(fold.op == Operator::FOLD_INF);
 
     std::string accumName = fold.bindings[0];
     llvm::Value* accumInit = scope->process(fold.getOperands()[0]);
 
     llvm::BasicBlock *blockBeforeLoop = llvm->builder.GetInsertBlock();
     llvm::BasicBlock *blockLoop = llvm::BasicBlock::Create(llvm::getGlobalContext(), "foldinf", function->raw);
     llvm::BasicBlock *blockNext = llvm::BasicBlock::Create(llvm::getGlobalContext(), "foldinf_next", function->raw);
     llvm::BasicBlock *blockAfterLoop = llvm::BasicBlock::Create(llvm::getGlobalContext(), "foldinf_post", function->raw);
     std::unique_ptr<TransformerSaturation> transformerSaturation(new TransformerSaturation(blockBeforeLoop, context.pass->managerTransformations));
 
     llvm->builder.CreateBr(blockLoop);
 
     // * create phi
     llvm->builder.SetInsertPoint(blockLoop);
     llvm::PHINode *accum = llvm->builder.CreatePHI(accumInit->getType(), 2, accumName);
     accum->addIncoming(accumInit, blockBeforeLoop);
 
     // * loop body
     CodeScope* scopeLoop = fold.blocks.front();
     compilation::ICodeScopeUnit* unitLoop = function->getScopeUnit(scopeLoop);
     unitLoop->bindArg(accum, move(accumName));
     Value* accumNext = unitLoop->compile();
 
     // * Loop saturation checks
     bool flagSaturationTriggered = transformerSaturation->insertSaturationChecks(blockNext, blockAfterLoop, context);
     assert(flagSaturationTriggered);
 
     // * computing next iteration state
     llvm->builder.SetInsertPoint(blockNext);
     accum->addIncoming(accumNext, llvm->builder.GetInsertBlock());
     llvm->builder.CreateBr(blockLoop);
 
     // finalization:
     llvm->builder.SetInsertPoint(blockAfterLoop);
     return accumNext;
 }
 
 llvm::Value*
-Advanced::compileIf(const Expression& exprIf, const std::string& hintRetVar) {
+AdvancedInstructions::compileIf(const Expression& exprIf, const std::string& hintRetVar) {
     EXPAND_CONTEXT
 
             //initialization:
     const Expression& condExpr = exprIf.getOperands()[0];
     llvm::IRBuilder<>& builder = llvm->builder;
     //llvm::Type* tyResultType = llvm->toLLVMType(llvm->ast->expandType(exprIf.type));
 
     llvm::BasicBlock *blockAfter = llvm::BasicBlock::Create(llvm::getGlobalContext(), "ifAfter", function->raw);
     llvm::BasicBlock *blockTrue = llvm::BasicBlock::Create(llvm::getGlobalContext(), "ifTrue", function->raw);
     llvm::BasicBlock *blockFalse = llvm::BasicBlock::Create(llvm::getGlobalContext(), "ifFalse", function->raw);
 
     llvm::Value* cond = scope->process(condExpr);
     llvm->builder.CreateCondBr(cond, blockTrue, blockFalse);
 
     builder.SetInsertPoint(blockTrue);
     CodeScope* scopeTrue = exprIf.blocks.front();
     llvm::Value* resultTrue = function->getScopeUnit(scopeTrue)->compile();
     blockTrue = builder.GetInsertBlock();
     builder.CreateBr(blockAfter);
 
     builder.SetInsertPoint(blockFalse);
     CodeScope* scopeFalse = exprIf.blocks.back();
     llvm::Value* resultFalse = function->getScopeUnit(scopeFalse)->compile();
     blockFalse = builder.GetInsertBlock();
     builder.CreateBr(blockAfter);
 
     builder.SetInsertPoint(blockAfter);
     llvm::PHINode *ret = builder.CreatePHI(resultTrue->getType(), 2, NAME("if"));
 
     ret->addIncoming(resultTrue, blockTrue);
     ret->addIncoming(resultFalse, blockFalse);
 
     return ret;
 }
 
 //TODO Switch: default variant no needed when all possible conditions are considered
-
 llvm::Value*
-Advanced::compileSwitch(const Expression& exprSwitch, const std::string& hintRetVar) {
+AdvancedInstructions::compileSwitch(const Expression& exprSwitch, const std::string& hintRetVar) {
     EXPAND_CONTEXT
-    AST* root = context.pass->man->root;
     UNUSED(function);
-
-
+    AST* root = context.pass->man->root;
+    llvm::IRBuilder<>& builder = llvm->builder;
     assert(exprSwitch.operands.size() >= 2);
     assert(exprSwitch.operands[1].op == Operator::CASE_DEFAULT && "No default case in Switch Statement");
-    int countCases = exprSwitch.operands.size() - 1;
-    llvm::IRBuilder<>& builder = llvm->builder;
 
+    int countCases = exprSwitch.operands.size() - 1;
     llvm::BasicBlock* blockProlog = builder.GetInsertBlock();
     llvm::BasicBlock *blockEpilog = llvm::BasicBlock::Create(llvm::getGlobalContext(), "switchAfter", function->raw);
     builder.SetInsertPoint(blockEpilog);
     llvm::Type* exprSwitchType = llvm->toLLVMType(root->getType(exprSwitch));
     llvm::PHINode *ret = builder.CreatePHI(exprSwitchType, countCases, NAME("switch"));
 
     builder.SetInsertPoint(blockProlog);
     llvm::Value * conditionSwitch = scope->process(exprSwitch.operands[0]);
     llvm::BasicBlock *blockDefault = llvm::BasicBlock::Create(llvm::getGlobalContext(), "caseDefault", function->raw);
     llvm::SwitchInst * instructionSwitch = builder.CreateSwitch(conditionSwitch, blockDefault, countCases);
 
     for (int size = exprSwitch.operands.size(), i = 2; i < size; ++i) {
         llvm::BasicBlock *blockCase = llvm::BasicBlock::Create(llvm::getGlobalContext(), "case" + std::to_string(i), function->raw);
 
         llvm::Value* condCase = function->getScopeUnit(exprSwitch.operands[i].blocks.front())->compile();
         builder.SetInsertPoint(blockCase);
         llvm::Value* resultCase = function->getScopeUnit(exprSwitch.operands[i].blocks.back())->compile();
         builder.CreateBr(blockEpilog);
 
         ret->addIncoming(resultCase, builder.GetInsertBlock());
         builder.SetInsertPoint(blockProlog);
         instructionSwitch->addCase(dyn_cast<llvm::ConstantInt>(condCase), blockCase);
     }
 
     //compile default block:
     builder.SetInsertPoint(blockDefault);
     CodeScope* scopeDefault = exprSwitch.operands[1].blocks.front();
     llvm::Value* resultDefault = function->getScopeUnit(scopeDefault)->compile();
     builder.CreateBr(blockEpilog);
     ret->addIncoming(resultDefault, builder.GetInsertBlock());
     builder.SetInsertPoint(blockEpilog);
 
     return ret;
 }
 
+llvm::Value*
+AdvancedInstructions::compileSwitchVariant(const Expression& exprSwitch, const std::string& hintRetVar) {
+    EXPAND_CONTEXT
+    UNUSED(function);
+    AST* root = context.pass->man->root;
+    llvm::IRBuilder<>& builder = llvm->builder;
+    llvm::Type* typI8= llvm::Type::getInt8Ty(llvm::getGlobalContext());
+    const ExpandedType& typVariant = root->getType(exprSwitch.operands.at(0));
+    llvm::Type* typVariantRaw = llvm->toLLVMType(typVariant);
+    llvm::Type* typStorageRaw = llvm::cast<llvm::StructType>(typVariantRaw)->getElementType(1);
+    assert(typVariant->__operands.size() == exprSwitch.operands.size() - 1 && "Ill-formed Switch Variant");
+
+    int casesCount = exprSwitch.operands.size();
+    llvm::BasicBlock* blockProlog = builder.GetInsertBlock();
+    llvm::BasicBlock *blockEpilog = llvm::BasicBlock::Create(llvm::getGlobalContext(), "switchAfter", function->raw);
+    builder.SetInsertPoint(blockEpilog);
+    llvm::Type* resultType = llvm->toLLVMType(root->getType(exprSwitch));
+    llvm::PHINode *ret = builder.CreatePHI(resultType, casesCount, NAME("switch"));
+
+    builder.SetInsertPoint(blockProlog);
+    llvm::Value * conditionSwitchRaw = scope->process(exprSwitch.operands.at(0));
+    llvm::Value* idRaw = builder.CreateExtractValue(conditionSwitchRaw, llvm::ArrayRef<unsigned>({0}));
+    llvm::Value* storageRaw = builder.CreateExtractValue(conditionSwitchRaw, llvm::ArrayRef<unsigned>({1}));
+    llvm::Value* addrAsStorage = llvm->builder.CreateAlloca(typStorageRaw);
+    llvm->builder.CreateStore(storageRaw, addrAsStorage);
+
+    string identCondition = exprSwitch.bindings.front();
+    llvm::SwitchInst * instructionSwitch = builder.CreateSwitch(idRaw, nullptr, casesCount);
+    llvm::BasicBlock* blockDefaultAmbiguous;
+
+    std::list<CodeScope*>::const_iterator scopeCaseIt = exprSwitch.blocks.begin();
+    for (int instancesSize = exprSwitch.operands.size()-1, instId = 0; instId < instancesSize; ++instId) {
+        llvm::BasicBlock *blockCase = llvm::BasicBlock::Create(llvm::getGlobalContext(), "case" + std::to_string(instId), function->raw);
+        builder.SetInsertPoint(blockCase);
+        ICodeScopeUnit* unitCase = function->getScopeUnit(*scopeCaseIt);
+
+        //derefence variant
+        const ExpandedType& instType = ExpandedType(typVariant->__operands.at(instId));
+        llvm::Type* instTypeRaw = llvm->toLLVMType(instType);
+        llvm::Value* addrAsInst =  llvm->builder.CreateBitOrPointerCast(addrAsStorage, instTypeRaw->getPointerTo());
+        llvm::Value* instRaw = llvm->builder.CreateLoad(instTypeRaw, addrAsInst);
+        const Symbol& identSymb =  unitCase->bindArg(instRaw, move(identCondition));
+        Attachments::put<TypeInferred>(identSymb, instType);
+
+        llvm::Value* resultCase = function->getScopeUnit(*scopeCaseIt)->compile();
+        builder.CreateBr(blockEpilog);
+
+        ret->addIncoming(resultCase, blockDefaultAmbiguous = builder.GetInsertBlock());
+        builder.SetInsertPoint(blockProlog);
+        instructionSwitch->addCase(dyn_cast<llvm::ConstantInt>(llvm::ConstantInt::get(typI8, exprSwitch.operands.at(instId+1).getValueDouble())), blockCase);
+        ++scopeCaseIt;
+    }
+
+    instructionSwitch->setDefaultDest(blockDefaultAmbiguous);
+    builder.SetInsertPoint(blockEpilog);
+    return ret;
+}
+
 //TODO recognize cases to make const arrays/stored in global mem/stack alloced.
 llvm::Value*
-Advanced::compileListAsSolidArray(const Expression &expr, const std::string& hintRetVar) {
+AdvancedInstructions::compileListAsSolidArray(const Expression &expr, const std::string& hintRetVar) {
     EXPAND_CONTEXT
     UNUSED(scope);
     UNUSED(function);
 
     AST* root = context.pass->man->root;
     const size_t& length = expr.getOperands().size();
     const Expression& expression = expr;
     llvm::Value* zero = ConstantInt::get(tyNum, 0);
     llvm::Value* one = ConstantInt::get(tyNum, 1);
 
     ExpandedType typAggrExpanded = root->getType(expression);
     assert(typAggrExpanded->__operator == TypeOperator::ARRAY);
     llvm::Type* typEl = llvm->toLLVMType(ExpandedType(typAggrExpanded->__operands[0]));
     ArrayType* typAggr = (ArrayType*) llvm::ArrayType::get(typEl, length);
     llvm::Value* list = llvm->builder.CreateAlloca(typAggr, ConstantInt::get(Type::getInt32Ty(llvm::getGlobalContext()), length, false), hintRetVar);
 
     const std::vector<Expression>& operands = expression.getOperands();
     llvm::Value* addrOperand = llvm->builder.CreateGEP(typAggr, list, ArrayRef<Value *>(std::vector<Value*>{zero, zero}));
     llvm->builder.CreateStore(scope->process(operands.front()), addrOperand) ;
     for (auto i=++operands.begin(); i!=operands.end(); ++i){
         addrOperand = llvm->builder.CreateGEP(typEl, addrOperand, ArrayRef<Value *>(std::vector<Value*>{one}));
         llvm->builder.CreateStore(scope->process(*i), addrOperand) ;
     }
 
     return list;
 //        Value* listDest = l.builder.CreateAlloca(typList, ConstantInt::get(typI32, __size), *hintRetVar);
 //        l.buil1der.CreateMemCpy(listDest, listSource, __size, 16);
 }
 
 llvm::Value*
-        Advanced::compileConstantStringAsPChar(const string& data, const std::string& hintRetVar) {
+        AdvancedInstructions::compileConstantStringAsPChar(const string& data, const std::string& hintRetVar) {
     EXPAND_CONTEXT
     UNUSED(function);
             UNUSED(scope);
 
             Type* typPchar = PointerType::getUnqual(Type::getInt8Ty(llvm::getGlobalContext()));
             //ArrayType* typStr = (ArrayType*) (llvm->toLLVMType(ExpandedType(TypeAnnotation(tag_array, TypePrimitive::I8, size+1))));
 
             /*
             std::vector<Constant *> chars;
             chars.reserve(size+1);
 
             for (size_t i=0; i< size; ++i){
                 chars[i] = ConstantInt::get(typI8, (unsigned char) data[i]);
             }
             chars[size] = ConstantInt::get(typI8, 0);
              */
 
             Value* rawData = ConstantDataArray::getString(llvm::getGlobalContext(), data);
             Value* rawPtrData = llvm->builder.CreateAlloca(rawData->getType(), ConstantInt::get(Type::getInt32Ty(llvm::getGlobalContext()), 1, false));
             llvm->builder.CreateStore(rawData, rawPtrData);
     return llvm->builder.CreateCast(llvm::Instruction::BitCast, rawPtrData, typPchar, hintRetVar);
 }
diff --git a/cpp/src/compilation/advanced.h b/cpp/src/compilation/advancedinstructions.h
similarity index 88%
rename from cpp/src/compilation/advanced.h
rename to cpp/src/compilation/advancedinstructions.h
index 76f4c4f..5c7bd16 100644
--- a/cpp/src/compilation/advanced.h
+++ b/cpp/src/compilation/advancedinstructions.h
@@ -1,52 +1,53 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
- * File:   InstructionsAdvanced.h
+ * File:   AdvancedInstructions.h
  * Author: pgess <v.melnychenko@xreate.org>
  *
  * Created on June 26, 2016, 6:00 PM
  */
 
 #ifndef INSTRUCTIONSADVANCED_H
 #define INSTRUCTIONSADVANCED_H
 
 #include "ast.h"
 #include "llvmlayer.h"
 #include "pass/compilepass.h"
 
 #include <vector>
 
 namespace xreate {
     namespace compilation {
 
-class Advanced {
+class AdvancedInstructions {
 public:
-    Advanced(compilation::Context ctx);
+    AdvancedInstructions(compilation::Context ctx);
     llvm::Value* compileArrayIndex(llvm::Value* aggregate, std::vector<llvm::Value *> indexes, std::string ident = "");
     llvm::Value* compileStructIndex(llvm::Value* aggregate, const ExpandedType& t, const std::string& idx);
         /*
         *    - map Computation -> Llvm_Array: Prohibited, we do not know a result size
         *    - map Llvm_Array -> Computation: considered in `compileGetElement`
         *    - map Llvm_Array -> Llvm_Array considered by this method
         */
     llvm::Value* compileMapSolidOutput(const Expression &expr, const std::string hintRetVar = "");
     llvm::Value* compileFold(const Expression& fold, const std::string& ident="");
     llvm::Value* compileFoldInf(const Expression& fold, const std::string& ident="");
     
     //DISABLEDFEATURE Context Loop
     llvm::Value* compileLoopContext(const Expression& expression, const std::string& hintRetVar);
     llvm::Value* compileIf(const Expression& exprIf, const std::string& ident);
     llvm::Value* compileSwitch(const Expression& exprSwitch, const std::string& hintRetVar);
+    llvm::Value* compileSwitchVariant(const Expression& exprSwitch, const std::string& hintRetVar);
     llvm::Value* compileConstantStringAsPChar(const std::string &data, const std::string& hintRetVar);
-    llvm::Value* compileListAsSolidArray(const Expression &expr, const std::string&  hintRetVar="");
+    llvm::Value* compileListAsSolidArray(const Expression &expr, const std::string&  hintRetVar);
 
 private:
     compilation::Context context;
     llvm::IntegerType* const tyNum;
 };
 
 }}
 
 #endif /* INSTRUCTIONSADVANCED_H */
 
diff --git a/cpp/src/compilation/containers.cpp b/cpp/src/compilation/containers.cpp
index 5735440..8999d93 100644
--- a/cpp/src/compilation/containers.cpp
+++ b/cpp/src/compilation/containers.cpp
@@ -1,206 +1,206 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * File:   containers.cpp
  * Author: pgess <v.melnychenko@xreate.org>
  *
  * \file    compilation/containers.h
  * \brief   Containers compilation support. See more [details on Containers](/w/concepts/containers)
  */
 
 #include "compilation/containers.h"
 
 using namespace std;
 using namespace llvm;
 using namespace xreate;
 using namespace xreate::containers;
 
 Iterator*
 Iterator::create(xreate::compilation::Context context, const xreate::Symbol& var){
 
 const Implementation& data = Query::queryImplementation(var);
 
 switch(data.impl){
     case ON_THE_FLY:
         return new IteratorForward<ON_THE_FLY>(context, var, data.extract<ON_THE_FLY>());
 
     case SOLID:
         return new IteratorForward<SOLID>(context, var, data.extract<SOLID>());
 
     default: assert(true);
 }
 
 assert(false && "Unknown declaration");
 return nullptr;
 }
 
 llvm::Value*
 IteratorForward<ON_THE_FLY>::begin() {
     switch(sourceDecl.op) {
         case xreate::Operator::LIST:
         {
             sourceRawType = llvm::Type::getInt32Ty(llvm::getGlobalContext());
             return llvm::ConstantInt::get(Type::getInt32Ty(llvm::getGlobalContext()), 0);
         };
 
         case xreate::Operator::LIST_RANGE:{
             assert(sourceDecl.operands.size()==2);
 
             llvm::Value* result = sourceUnit->process(sourceDecl.operands.at(0));
             sourceRawType = result->getType();
 
             return result;
         };
 
         default: break;
     }
 
     if (linkedlist){
         llvm::Value* result = sourceUnit->process(sourceDecl);
         sourceRawType = result->getType();
        return result;
     }
 
     assert(false);
 }
 
 llvm::Value*
 IteratorForward<ON_THE_FLY>::end(){
     switch(sourceDecl.op) {
         case xreate::Operator::LIST: {
             size_t idLast = sourceDecl.operands.size() - 1;
             return ConstantInt::get(sourceRawType, idLast);
         }
 
         case xreate::Operator::LIST_RANGE: {
             assert(sourceDecl.operands.size() == 2);
             llvm::Value* valueEndOfRange =  sourceUnit->process(sourceDecl.operands.at(1));
             llvm::Value* valueConstOne = llvm::ConstantInt::get(llvm::Type::getInt32Ty(llvm::getGlobalContext()), 1);
 
             return llvm->builder.CreateAdd(valueEndOfRange, valueConstOne);
         };
 
     default: break;
     }
 
                 //return null pointer
     if (linkedlist){
             return ConstantPointerNull::getNullValue(sourceRawType);
     }
 
     assert(false && "Unknown declaration");
     return nullptr;
 }
 
 llvm::Value*
 IteratorForward<ON_THE_FLY>::get(Value* index,const std::string& hintRetVar){
     const Expression& currentDecl = CodeScope::getDefinition(current);
 
     switch (currentDecl.op) {
         case xreate::Operator::LIST:             {
             //TODO re check is it right scope(source) to compile currentDecl. Provide unittests.
             llvm::Value* currentValue = sourceUnit->processSymbol(current);
-            return xreate::compilation::Advanced(context).compileArrayIndex(currentValue, std::vector<Value *>{index});
+            return xreate::compilation::AdvancedInstructions(context).compileArrayIndex(currentValue, std::vector<Value *>{index});
         };
 
         case xreate::Operator::LIST_RANGE: {
             return index;
         };
 
         case xreate::Operator::MAP:             {
             assert(currentDecl.getOperands().size()==1);
             assert(currentDecl.bindings.size());
             assert(currentDecl.blocks.size());
 
             CodeScope* scopeLoop = currentDecl.blocks.front();
             std::string varEl = currentDecl.bindings[0];
 
             const Symbol& symbIn = Attachments::get<IdentifierSymbol>(currentDecl.getOperands()[0]);
             auto it = std::unique_ptr<Iterator>(Iterator::create(context, symbIn));
 
             Value* elIn = it->get(index, varEl);
             compilation::ICodeScopeUnit* unitLoop = function->getScopeUnit(scopeLoop);
             unitLoop->bindArg(elIn, std::move(varEl));
             return unitLoop->compile();
         }
 
         case xreate::Operator::NONE: {
             //TODO review iterator determination strategy for case of Expression::BINDING
             assert(currentDecl.__state==Expression::IDENT);
 
             const Symbol& symbIn =  Attachments::get<IdentifierSymbol>(currentDecl);
             auto it = std::unique_ptr<Iterator>(Iterator::create(context, symbIn));
             return it->get(index);
         };
 
         default: break;
     }
 
     if (linkedlist){
         return index;
     }
 
     assert(false && "Unknown declaration");
     return nullptr;
 }
 
 llvm::Value*
 IteratorForward<ON_THE_FLY>::advance(Value* index, const std::string& hintRetVar){
     switch(sourceDecl.op)
     {
         case xreate::Operator::LIST:
         case xreate::Operator::LIST_RANGE:
             return llvm->builder.CreateAdd(index, llvm::ConstantInt::get(llvm::Type::getInt32Ty(llvm::getGlobalContext()), 1), hintRetVar);
 
         default: break;
     }
 
     if (linkedlist){
         ExpandedType tySource = llvm->ast->getType(CodeScope::getDefinition(source));
         assert(tySource->__operator == TypeOperator::ARRAY && "Linked list implementation has to have ARRAY type");
         assert(tySource->__operands.size());
 
-        return xreate::compilation::Advanced(context).compileStructIndex(index, ExpandedType(TypeAnnotation(tySource->__operands.at(0))), linkedlist.fieldPointer);
+        return xreate::compilation::AdvancedInstructions(context).compileStructIndex(index, ExpandedType(TypeAnnotation(tySource->__operands.at(0))), linkedlist.fieldPointer);
     }
 
     assert(false && "Unknown declaration");
     return nullptr;
 }
 
 //const ImplementationRec<ON_THE_FLY>& implementation
 
 IteratorForward<SOLID>::IteratorForward(const compilation::Context& ctx,  const xreate::Symbol& symbolContainer, const ImplementationRec<SOLID>& implementation)
     : Iterator(), __length(implementation.size), llvm(ctx.pass->man->llvm)
 {
     __container = ctx.function->getScopeUnit(symbolContainer.scope)->processSymbol(symbolContainer);
 }
 
 llvm::Value*
 IteratorForward<SOLID>::begin(){
     //0
     return llvm::ConstantInt::get(llvm::Type::getInt32Ty(llvm::getGlobalContext()), 0);
 }
 
 llvm::Value*
 IteratorForward<SOLID>::end(){
     //length
     return llvm::ConstantInt::get(llvm::Type::getInt32Ty(llvm::getGlobalContext()), __length);
 }
 
 llvm::Value*
 IteratorForward<SOLID>::get(llvm::Value* index,const std::string& hintRetVar){
     //GEP[index]]
 
     llvm::Type* tyNum = llvm::Type::getInt32Ty(llvm::getGlobalContext());
     llvm::Value* pResult = llvm->builder.CreateGEP(__container, ArrayRef<Value *>(std::vector<Value*>{ConstantInt::get(tyNum, 0), index}));
     return llvm->builder.CreateLoad(pResult, hintRetVar);
 }
 
 llvm::Value*
 IteratorForward<SOLID>::advance(llvm::Value* index, const std::string& hintRetVar){
     //index + 1
 
     llvm::Type* tyNum = llvm::Type::getInt32Ty(llvm::getGlobalContext());
     return llvm->builder.CreateAdd(index, llvm::ConstantInt::get(tyNum, 1), hintRetVar);
 }
diff --git a/cpp/src/compilation/containers.h b/cpp/src/compilation/containers.h
index 5a190f3..6fa52d9 100644
--- a/cpp/src/compilation/containers.h
+++ b/cpp/src/compilation/containers.h
@@ -1,98 +1,98 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * File:   containers.h
  * Author: pgess <v.melnychenko@xreate.org>
  */
 
 #ifndef CODEINSTRUCTIONS_H
 #define CODEINSTRUCTIONS_H
 
 #include "ast.h"
 
 #include "llvmlayer.h"
 #include "pass/compilepass.h"
-#include "compilation/advanced.h"
+#include "compilation/advancedinstructions.h"
 
 #include "query/context.h"
 #include "query/containers.h"
 
 namespace xreate {
     namespace containers {
 
 using namespace llvm;
 
 /** \brief Factory to create relevant iterator based on solution 
  * provided by xreate::containers::Query
  * \sa xreate::containers::Query
  */
 class Iterator{
 public :
     virtual llvm::Value* begin() =0;
     virtual llvm::Value* end() = 0;
     virtual llvm::Value* get(llvm::Value* index,const std::string& hintRetVar="") = 0;
     virtual llvm::Value* advance(llvm::Value* index, const std::string& hintRetVar="")=0;
     virtual ~Iterator(){};
 
     static Iterator* create(xreate::compilation::Context context, const xreate::Symbol& var);
 };
 
 template<ImplementationType I>
 class IteratorForward;
 
 /** \brief Possible container implementation. Represents computation on the fly 
  *  \sa xreate::containers::Iterator, \sa xreate::containers::Query
  */
 template<>
 class IteratorForward<ON_THE_FLY> : public Iterator {
 private:
     LLVMLayer* llvm;
     const xreate::Symbol current;
     const Symbol source;
     const ImplementationLinkedList linkedlist;
-    CodeScope* const sourceScope;
+    const CodeScope* const sourceScope;
             //TODO initialize and mark as const (three fields)
     compilation::ICodeScopeUnit* sourceUnit;
     compilation::IFunctionUnit* function; //TODO is used somewhere?
     const Expression& sourceDecl;
     compilation::Context context;
     llvm::Type* sourceRawType =nullptr;
 
 public:
     IteratorForward(const compilation::Context& ctx, const xreate::Symbol& s, const ImplementationRec<ON_THE_FLY>& implementation)
     :   llvm(ctx.pass->man->llvm), 
         current(s), 
         source(implementation.source), 
         linkedlist(source), 
         sourceScope(source.scope),
         sourceUnit(ctx.function->getScopeUnit(source.scope)),
         sourceDecl(CodeScope::getDefinition(source)),
         context(ctx)
     {}
     
     llvm::Value* begin() override;
     llvm::Value* end() override;
     llvm::Value* get(llvm::Value* index,const std::string& hintRetVar="") override;
     llvm::Value* advance(llvm::Value* index, const std::string& hintRetVar="") override;
 };
 
 /** \brief Possible container implementation. Represents contiguous in memory(array) implementation
  *  \sa xreate::containers::Iterator, \sa xreate::containers::Query
  */
 template<>
 class IteratorForward<SOLID>: public Iterator{
     size_t __length;
     llvm::Value* __container;
     LLVMLayer* llvm;
     
 public:
     IteratorForward(const compilation::Context& ctx, const xreate::Symbol& symbolContainer, const ImplementationRec<SOLID>& implementation);
     llvm::Value* begin() override;
     llvm::Value* end() override;
     llvm::Value* get(llvm::Value* index,const std::string& hintRetVar="") override;
     llvm::Value* advance(llvm::Value* index, const std::string& hintRetVar="") override;
 };
 }}
 
 #endif //CODEINSTRUCTIONS_H
diff --git a/cpp/src/compilation/polymorphcompiler.h b/cpp/src/compilation/polymorphcompiler.h
index d2c933e..fcc7382 100644
--- a/cpp/src/compilation/polymorphcompiler.h
+++ b/cpp/src/compilation/polymorphcompiler.h
@@ -1,55 +1,55 @@
 /*
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * File:   polymorphcompiler.h
  * Author: pgess <v.melnychenko@xreate.org>
  *
  * Created on October 7, 2017
  */
 
 #ifndef POLYMORPHCOMPILER_H
 #define POLYMORPHCOMPILER_H
 
 #include "pass/compilepass.h"
 #include "query/polymorph.h"
 
 namespace xreate { namespace polymorph {
 
 typedef Expression Guard;    
     
 template <class Parent>
 class PolymorphCodeScopeUnit: public Parent{
 public:
-    PolymorphCodeScopeUnit(CodeScope* codeScope, compilation::IFunctionUnit* f, CompilePass* compilePass)
+    PolymorphCodeScopeUnit(const CodeScope* const codeScope, compilation::IFunctionUnit* f, CompilePass* compilePass)
             : Parent(codeScope, f, compilePass) {}
 
 protected:
     compilation::ICallStatement* findFunction(const Expression& opCall) override {
         
         //Check does invocation require guards
         const std::string& nameCallee = opCall.getValueString();
         const std::list<ManagedFnPtr>& specializations = Parent::pass->man->root->getFunctionSpecializations(nameCallee);
         if (specializations.size() == 1){
             if (!specializations.front()->guard.isValid()) {
                 return Parent::findFunction(opCall);
             }
         }
         
         assert(Attachments::exists<PolymorphGuard>(opCall) && "Guard required");
         const Expression& guardSelected = Attachments::get<PolymorphGuard>(opCall);
         std::map<Guard, ManagedFnPtr> indexSpecs;
         for(ManagedFnPtr specialization: specializations){
             indexSpecs.emplace(specialization->guard, specialization);
         }
         
         assert(indexSpecs.count(guardSelected) && "Can't found appropriate guard");
         return new compilation::CallStatementRaw(Parent::pass->getFunctionUnit(indexSpecs.at(guardSelected))->compile(), Parent::pass->man->llvm);
     }
 };
 
 } } //end of xreate::polymorph
 
 #endif /* POLYMORPHCOMPILER_H */
 
diff --git a/cpp/src/compilation/scopedecorators.h b/cpp/src/compilation/scopedecorators.h
index 54e7a23..b0e66ec 100644
--- a/cpp/src/compilation/scopedecorators.h
+++ b/cpp/src/compilation/scopedecorators.h
@@ -1,145 +1,147 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * File:   scopedecorators.h
  * Author: pgess <v.melnychenko@xreate.org>
  *
  * Created on February 24, 2017, 11:35 AM
  */
 
 /**
  * \file    scopedecorators.h
  * \brief   Basic code block compilation xreate::compilation::ICodeScopeUnit  decorators
  */
 
 
 #ifndef SCOPEDECORATORS_H
 #define SCOPEDECORATORS_H
 
 #include "ast.h"
 #include "compilation/targetinterpretation.h"
 #include "compilation/versions.h"
 #include "compilation/transformations.h"
 #include "compilation/polymorphcompiler.h"
 
 namespace xreate { 
     
 class CompilePass;
 
 namespace compilation {
 
 class ICodeScopeUnit;
 class IFunctionUnit;
 
 /**\brief Caching ability for code scope compilation
  * \extends xreate::compilation::ICodeScopeUnit
  */
 template<class Parent>
 class CachedScopeDecorator: public Parent{
     typedef CachedScopeDecorator<Parent> SELF;
 
 public:
-    CachedScopeDecorator(CodeScope* codeScope, IFunctionUnit* f, CompilePass* compilePass): Parent(codeScope, f, compilePass){}
+    CachedScopeDecorator(const CodeScope* const codeScope, IFunctionUnit* f, CompilePass* compilePass): Parent(codeScope, f, compilePass){}
 
-    void bindArg(llvm::Value* value, std::string&& alias)
+    Symbol bindArg(llvm::Value* value, std::string&& alias)
     {
         //ensure existence of an alias
         assert(Parent::scope->__identifiers.count(alias));
 
         //memorize new value for an alias
         ScopedSymbol id{Parent::scope->__identifiers.at(alias), versions::VERSION_NONE};
         __rawVars[id] = value;
+        
+        return Symbol{id, Parent::scope};
     }
 
     void bindArg(llvm::Value* value, const ScopedSymbol& s) {
         __rawVars[s] = value;
     }
     
     llvm::Value* compile(const std::string& hintBlockDecl="") override{
         if (__rawVars.count(ScopedSymbol::RetSymbol)){
             return __rawVars[ScopedSymbol::RetSymbol];
         }
         
         return Parent::compile(hintBlockDecl);
     }
 
     llvm::Value* 
     processSymbol(const Symbol& s, std::string hintRetVar) override{
-        CodeScope* scope = s.scope;
+        const CodeScope* scope = s.scope;
         SELF* self = dynamic_cast<SELF*>(Parent::function->getScopeUnit(scope));
 
         if (self->__rawVars.count(s.identifier)){
             return self->__rawVars[s.identifier];
         }
 
         //Declaration could be overriden
         Expression declaration = CodeScope::getDefinition(s, true);
         if (!declaration.isDefined()){
             if (self->__declarationsOverriden.count(s.identifier)){
                 declaration = self->__declarationsOverriden[s.identifier];
 
             } else {
                 assert(false); //in case of binding there should be raws provided.
             }
         }
 
         return self->__rawVars[s.identifier] = Parent::processSymbol(s, hintRetVar);
     }
 
     void 
     overrideDeclaration(const Symbol binding, Expression&& declaration){
         SELF* self = dynamic_cast<SELF*>(Parent::function->getScopeUnit(binding.scope));
 
         self->__declarationsOverriden.emplace(binding.identifier, std::move(declaration));
     }
 
     void registerChildScope(std::shared_ptr<ICodeScopeUnit> scope){
         __childScopes.push_back(scope);
     }
 
     void reset(){
         __rawVars.clear();
         __declarationsOverriden.clear();
         __childScopes.clear();
     }
 
 private:
     std::unordered_map<ScopedSymbol, Expression> __declarationsOverriden;
     std::unordered_map<ScopedSymbol,llvm::Value*> __rawVars;
     std::list<std::shared_ptr<ICodeScopeUnit>> __childScopes;
 };
 
 /**\brief Default code scope compilation functionality*/
 typedef CachedScopeDecorator<
         polymorph::PolymorphCodeScopeUnit<
         ::xreate::compilation::TransformationsScopeDecorator<
         interpretation::InterpretationScopeDecorator<
         versions::VersionsScopeDecorator<compilation::BasicCodeScopeUnit>>>>>
 
         DefaultCodeScopeUnit;
 
 } //end of compilation namespace
 
 struct CachedScopeDecoratorTag;
 struct VersionsScopeDecoratorTag;
 
 template<>
 struct DecoratorsDict<CachedScopeDecoratorTag>{
     typedef compilation::CachedScopeDecorator<
             polymorph::PolymorphCodeScopeUnit<
             compilation::TransformationsScopeDecorator<
             interpretation::InterpretationScopeDecorator<
             versions::VersionsScopeDecorator<compilation::BasicCodeScopeUnit>>>>> result;
 };
 
 template<>
 struct DecoratorsDict<VersionsScopeDecoratorTag>{
     typedef versions::VersionsScopeDecorator<
             compilation::BasicCodeScopeUnit> result;
 };
 
 } //end of xreate
 
 #endif /* SCOPEDECORATORS_H */
 
diff --git a/cpp/src/compilation/targetinterpretation.cpp b/cpp/src/compilation/targetinterpretation.cpp
index 00637b1..6b61305 100644
--- a/cpp/src/compilation/targetinterpretation.cpp
+++ b/cpp/src/compilation/targetinterpretation.cpp
@@ -1,595 +1,595 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * File:   targetinterpretation.cpp
  * Author: pgess <v.melnychenko@xreate.org>
  *
  * Created on June 29, 2016, 6:45 PM
  */
 
 /**
  * \file    targetinterpretation.h
  * \brief   Interpretation support. See more [details on Interpretation](/w/concepts/dsl/)
  */
 
 #include "compilation/targetinterpretation.h"
 #include "pass/interpretationpass.h"
 #include "analysis/typeinference.h"
 #include "llvmlayer.h"
 #include "compilation/scopedecorators.h"
 
 #include <boost/scoped_ptr.hpp>
 #include <iostream>
 #include <clang/AST/DeclBase.h>
 
 using namespace std;
 using namespace xreate::compilation;
 
 namespace xreate{ namespace interpretation{
 
     const Expression EXPRESSION_FALSE = Expression(Atom<Number_t>(0));
     const Expression EXPRESSION_TRUE = Expression(Atom<Number_t>(1));
 
 Expression
 representAsAnnotation(const Gringo::Symbol& atom){
     switch (atom.type()) {
         case Gringo::SymbolType::Num: {
             Expression result(Operator::VARIANT, {Expression(atom.num())});
             result.setValueDouble(0);
             return result;
         }
 
         case Gringo::SymbolType::Str: {
             Expression result(Operator::VARIANT, {Expression(Atom<String_t>(std::string(atom.string().c_str())))});
             result.setValueDouble(1);
             return result;
         }
 
         case Gringo::SymbolType::Fun:
         {
             Expression fnDescription(Operator::LIST_NAMED, {});
             std::list<Atom<Identifier_t>> bindings{Atom<Identifier_t>("name"), Atom<Identifier_t>("arguments")};
             fnDescription.addBindings(bindings.begin(), bindings.end());
 
             fnDescription.addArg(Expression(Atom<String_t>(std::string(atom.name().c_str()))));
 
             Expression args(Operator::LIST, {});
             for (const Gringo::Symbol& arg : atom.args()) {
                 args.addArg(representAsAnnotation(arg));
             }
 
             fnDescription.addArg(std::move(args));
 
             Expression result(Operator::VARIANT, {fnDescription});
             result.setValueDouble(2);
             return result;
         }
 
         default:
         {
             assert(false);
         }
     }
 }
 
 CodeScope*
 InterpretationScope::processOperatorIf(const Expression& expression){
     const Expression& exprCondition = process(expression.getOperands()[0]);
 
     if (exprCondition == EXPRESSION_TRUE){
         return expression.blocks.front();
     }
 
     return expression.blocks.back();
 }
 
 CodeScope*
 InterpretationScope::processOperatorSwitch(const Expression& expression) {
     const Expression& exprCondition = process(expression.operands[0]);
 
     bool flagHasDefault = expression.operands[1].op == Operator::CASE_DEFAULT;
 
     //TODO check that one and only one case variant is appropriate
     for (size_t size = expression.operands.size(), i= flagHasDefault? 2: 1; i<size; ++i){
         const Expression& exprCase = process(expression.operands[i]);
 
-        if (function->getScope(exprCase.blocks.front())->processScope() == exprCondition){
+        if (function->getScope((const CodeScope*) exprCase.blocks.front())->processScope() == exprCondition){
             return exprCase.blocks.back();
         }
     }
 
     if (flagHasDefault){
         const Expression& exprCaseDefault = expression.operands[1];
         return exprCaseDefault.blocks.front();
     }
 
     assert(false && "Switch has no appropriate variant");
     return nullptr;
 }
 
 CodeScope*
 InterpretationScope::processOperatorSwitchVariant(const Expression& expression){
     const Expression& condition = process(expression.operands.at(0));
     assert(condition.op == Operator::VARIANT);
-    const string identCondition = expression.bindings.front();
+    const string& identCondition = expression.bindings.front();
 
     Expression opExpected(Atom<Number_t>(condition.getValueDouble()));
     auto itFoundValue = std::find(++expression.operands.begin(), expression.operands.end(), opExpected);
     assert(itFoundValue != expression.operands.end());
 
     int indexBlock = itFoundValue - expression.operands.begin() -1;
     auto blockFound = expression.blocks.begin();
     std::advance(blockFound, indexBlock);
 
     InterpretationScope* scopeI12n = function->getScope(*blockFound);
 
     if (condition.operands.size()) {
         const Expression& value = condition.operands.at(0);
         scopeI12n->overrideBinding(value, identCondition);
     }
 
     return *blockFound;
 }
 
 llvm::Value*
 InterpretationScope::compileHybrid(const InterpretationOperator& op, const Expression& expression, const Context& context){
     switch(op){
         case IF_INTERPRET_CONDITION: {
             CodeScope* scopeResult = processOperatorIf(expression);
 
             llvm::Value* result = context.function->getScopeUnit(scopeResult)->compile();
             return result;
         }
 
         case SWITCH_INTERPRET_CONDITION:{
             CodeScope* scopeResult = processOperatorSwitch(expression);
 
             llvm::Value* result = context.function->getScopeUnit(scopeResult)->compile();
             return result;
         }
 
         case SWITCH_VARIANT: {
             CodeScope* scopeResult = processOperatorSwitchVariant(expression);
             const Expression& condition = expression.operands.at(0);
             const Expression& valueCondition = process(condition);
 
             const string identCondition = expression.bindings.front();
             auto scopeCompilation = Decorators<CachedScopeDecoratorTag>::getInterface(context.function->getScopeUnit(scopeResult));
 
             if(valueCondition.operands.size()){
                 //override value
                 Symbol symbCondition{ScopedSymbol{scopeResult->__identifiers.at(identCondition), versions::VERSION_NONE}, scopeResult};
                 scopeCompilation->overrideDeclaration(symbCondition, Expression(valueCondition.operands.at(0)));
 
                 //set correct type for binding:
                 TypeAnnotation typeVariant = typeinference::getType(condition, *function->man->ast);
                 int conditionIndex = valueCondition.getValueDouble();
                 ScopedSymbol symbolInternal = scopeResult->getSymbol(identCondition);
                 scopeResult->__declarations[symbolInternal].bindType(typeVariant.__operands.at(conditionIndex));
             }
 
             llvm::Value* result = context.function->getScopeUnit(scopeResult)->compile();
             return result;
         }
 
         case FOLD_INTERPRET_INPUT: {
             //initialization
             const Expression& exprInput = process(expression.getOperands()[0]);
             assert(exprInput.op == Operator::LIST);
 
             CodeScope* scopeBody = expression.blocks.front();
 
             const string& nameEl = expression.bindings[0];
             Symbol symbEl{ScopedSymbol{scopeBody->__identifiers.at(nameEl), versions::VERSION_NONE}, scopeBody};
             const std::string& idAccum = expression.bindings[1];
             llvm::Value* rawAccum = context.scope->process(expression.getOperands()[1]);
 
             InterpretationScope* intrBody = function->getScope(scopeBody);
             auto unitBody = Decorators<CachedScopeDecoratorTag>::getInterface(context.function->getScopeUnit(scopeBody));
 
             const std::vector<Expression> elementsInput= exprInput.getOperands();
 
             for (size_t i=0; i<elementsInput.size(); ++i){
                 intrBody->reset();
                 unitBody->reset();
 
                 Expression exprElement  = elementsInput[i];
 
                 intrBody->overrideBinding(exprElement, nameEl);
                 unitBody->overrideDeclaration(symbEl, move(exprElement));
                 unitBody->bindArg(rawAccum, string(idAccum));
 
                 rawAccum = unitBody->compile();
             }
 
             return rawAccum;
         }
 
         /*
         case FOLD_INF_INTERPRET_INOUT{
         }
         */
 
         //TODO refactor as InterpretationCallStatement class
         case CALL_INTERPRET_PARTIAL: {
             const std::string &calleeName = expression.getValueString();
             ICodeScopeUnit* scopeUnitSelf = context.scope;
             ManagedFnPtr callee = this->function->man->ast->findFunction(calleeName);
             const  FunctionInterpretationData& calleeData = FunctionInterpretationHelper::getSignature(callee);
             std::vector<llvm::Value *> argsActual;
             PIFSignature sig;
             sig.declaration = callee;
 
             for(size_t no=0, size = expression.operands.size(); no < size; ++no){
                 const Expression& op =  expression.operands[no];
 
                 if (calleeData.signature.at(no) == INTR_ONLY){
                     sig.bindings.push_back(process(op));
                     continue;
                 }
 
                 argsActual.push_back(scopeUnitSelf->process(op));
             }
 
             TargetInterpretation* man = dynamic_cast<TargetInterpretation*>(this->function->man);
             PIFunction* pifunction =  man->getFunction(move(sig));
 
             llvm::Function* raw = pifunction->compile();
             boost::scoped_ptr<CallStatementRaw> statement(new CallStatementRaw(raw, man->pass->man->llvm));
             return (*statement)(move(argsActual));
         }
 
         default: break;
     }
 
     assert(false&& "Unknown hybrid operator");
     return nullptr;
 }
 
 llvm::Value*
 InterpretationScope::compile(const Expression& expression, const Context& context){
     const InterpretationData& data = Attachments::get<InterpretationData>(expression);
 
     if (data.op != InterpretationOperator::NONE){
         return compileHybrid(data.op, expression, context);
     }
 
     Expression result = process(expression);
     return context.scope->process(result);
 }
 
 Expression
 InterpretationScope::process(const Expression& expression){
     switch (expression.__state){
         case Expression::INVALID:
             assert(false);
 
         case Expression::NUMBER:
         case Expression::STRING:
             return expression;
 
         case Expression::IDENT:{
             Symbol s = Attachments::get<IdentifierSymbol>(expression);
             return Parent::processSymbol(s);
         }
 
         case Expression::COMPOUND:
             break;
 
         default: assert(false);
     }
 
     switch (expression.op) {
         case Operator::EQU: {
             const Expression& left = process(expression.operands[0]);
             const Expression& right = process(expression.operands[1]);
 
             if (left == right) return EXPRESSION_TRUE;
             return EXPRESSION_FALSE;
         }
 
         case Operator::NE: {
             const Expression& left = process(expression.operands[0]);
             const Expression& right = process(expression.operands[1]);
 
             if (left == right) return EXPRESSION_FALSE;
             return EXPRESSION_TRUE;
         }
 
         case Operator::LOGIC_AND: {
             assert(expression.operands.size() == 1);
             return process (expression.operands[0]);
         }
 
 
 //        case Operator::LOGIC_OR:
         case Operator::CALL: {
             const std::string &fnName = expression.getValueString();
             ManagedFnPtr fnAst = this->function->man->ast->findFunction(fnName);
             InterpretationFunction* fnUnit = this->function->man->getFunction(fnAst);
 
             vector<Expression> args;
             args.reserve(expression.getOperands().size());
 
             for(size_t i=0, size = expression.getOperands().size(); i<size; ++i) {
                 args.push_back(process(expression.getOperands()[i]));
             }
 
             return fnUnit->process(args);
         }
 
         case Operator::CALL_INTRINSIC: {
             std::string nameFunction = expression.getValueString();
 
             if(nameFunction=="query"){
                 assert(expression.operands.size() == 1);
                 assert(expression.operands.front().__state == Expression::STRING);
 
                 std::string namePredicate = expression.operands.front().getValueString();
                 ClaspLayer::ModelFragment model = (static_cast<TargetInterpretation*>(function->man))->pass->man->clasp->query(namePredicate);
 
                 Expression result(Operator::LIST, {});
 
                 if(model)
                 for (const auto& row: boost::make_iterator_range(model.get())) {
                     result.addArg(representAsAnnotation(std::get<1>(row)));
                 }
 
                 return result;
 
             } else {
                 assert(false && "Unknown intrinsic");
             }
         }
 
         case Operator::IF:{
             CodeScope* scopeResult = processOperatorIf(expression);
             return function->getScope(scopeResult)->processScope();
         }
 
         case Operator::SWITCH: {
             CodeScope* scopeResult = processOperatorSwitch(expression);
             return function->getScope(scopeResult)->processScope();
         }
 
         case Operator::SWITCH_VARIANT: {
             CodeScope* scopeResult = processOperatorSwitchVariant(expression);
             return function->getScope(scopeResult)->processScope();
         }
 
         case Operator::INDEX: {
             Expression exprData = process(expression.operands[0]);
 
             for (size_t keyId=1; keyId<expression.operands.size(); ++keyId){
                 const Expression& exprKey = process(expression.operands[keyId]);
 
                 if (exprKey.__state == Expression::STRING){
                     const string& key = exprKey.getValueString();
                     assert(exprData.__indexBindings.count(key));
                     size_t idxKey = exprData.__indexBindings.at(key);
 
                     exprData = Expression(exprData.operands.at(idxKey));
                     continue;
                 }
 
                 if (exprKey.__state == Expression::NUMBER){
                     int key = exprKey.getValueDouble();
                     exprData = Expression(exprData.operands[key]);
                     continue;
                 }
 
                 assert(false && "Inappropriate key");
             }
 
             return exprData;
         }
 
         case Operator::FOLD: {
             const Expression& exprInput = process(expression.getOperands()[0]);
             const Expression& exprInit = process(expression.getOperands()[1]);
 
             const std::string& argEl = expression.bindings[0];
             const std::string& argAccum = expression.bindings[1];
 
             InterpretationScope* body = function->getScope(expression.blocks.front());
 
             Expression accum = exprInit;
             for(size_t size=exprInput.getOperands().size(), i=0; i<size; ++i){
                 body->overrideBinding(exprInput.getOperands()[i], argEl);
                 body->overrideBinding(accum, argAccum);
 
                 accum = body->processScope();
             }
 
             return accum;
         }
 
 //        case Operator::MAP: {
 //            break;
 //        }
 
         default: break;
     }
 
     return expression;
 }
 
 InterpretationFunction*
 TargetInterpretation::getFunction(IFunctionUnit* unit){
     if (__dictFunctionsByUnit.count(unit)) {
         return __dictFunctionsByUnit.at(unit);
     }
 
     InterpretationFunction* f = new InterpretationFunction(unit->function, this);
     __dictFunctionsByUnit.emplace(unit, f);
     assert(__functions.emplace(unit->function.id(), f).second);
 
     return f;
 }
 
 PIFunction*
 TargetInterpretation::getFunction(PIFSignature&& sig){
 
     auto f = __pifunctions.find(sig);
     if (f != __pifunctions.end()){
         return f->second;
     }
 
     PIFunction* result  = new PIFunction(PIFSignature(sig), __pifunctions.size(), this);
     __pifunctions.emplace(move(sig), result);
     assert(__dictFunctionsByUnit.emplace(result->functionUnit, result).second);
 
     return result;
 }
 
 InterpretationScope*
 TargetInterpretation::transformContext(const Context& c){
     return this->getFunction(c.function)->getScope(c.scope->scope);
 }
 
 llvm::Value*
 TargetInterpretation::compile(const Expression& expression, const Context& ctx){
     return transformContext(ctx)->compile(expression, ctx);
 }
 
 InterpretationFunction::InterpretationFunction(const ManagedFnPtr& function, Target<TargetInterpretation>* target)
     : Function<TargetInterpretation>(function, target)
 {}
 
 Expression
 InterpretationFunction::process(const std::vector<Expression>& args){
     InterpretationScope* body = getScope(__function->__entry);
 
     for(size_t i=0, size = args.size(); i<size; ++i) {
         body->overrideBinding(args.at(i), string(body->scope->__bindings.at(i)));
     }
 
     return body->processScope();
 }
 
 //                  Partial function interpretation
 
 typedef BasicFunctionUnit PIFunctionUnitParent;
 class PIFunctionUnit: public PIFunctionUnitParent{
 public:
 
     PIFunctionUnit(ManagedFnPtr f, std::set<size_t>&& arguments, size_t id, CompilePass* p)
         : PIFunctionUnitParent(f,  p), argumentsActual(move(arguments)), __id(id)
     {}
 
 protected:
     std::vector<llvm::Type*> prepareArguments(){
         LLVMLayer* llvm = PIFunctionUnitParent::pass->man->llvm;
         AST* ast = PIFunctionUnitParent::pass->man->root;
         CodeScope* entry = PIFunctionUnitParent::function->__entry;
         std::vector<llvm::Type*> signature;
 
         for(size_t no: argumentsActual){
             VNameId argId = entry->__identifiers.at(entry->__bindings.at(no));
             ScopedSymbol arg{argId, versions::VERSION_NONE};
 
             signature.push_back(llvm->toLLVMType(ast->expandType(entry->__declarations.at(arg).type)));
         }
 
         return signature;
     }
 
     llvm::Function::arg_iterator prepareBindings(){
         CodeScope* entry = PIFunctionUnitParent::function->__entry;
         ICodeScopeUnit* entryCompilation = PIFunctionUnitParent::getScopeUnit(entry);
         llvm::Function::arg_iterator fargsI = PIFunctionUnitParent::raw->arg_begin();
 
         for(size_t no: argumentsActual){
             ScopedSymbol arg{entry->__identifiers.at(entry->__bindings.at(no)), versions::VERSION_NONE};
 
             entryCompilation->bindArg(&*fargsI, arg);
             fargsI->setName(entry->__bindings.at(no));
             ++fargsI;
         }
 
         return fargsI;
     }
 
     virtual std::string prepareName(){
         return PIFunctionUnitParent::prepareName() + "_" + std::to_string(__id);
     }
 
 private:
     std::set<size_t> argumentsActual;
     size_t __id;
 };
 
 PIFunction::PIFunction(PIFSignature&& sig, size_t id, TargetInterpretation* target)
     : InterpretationFunction(sig.declaration, target), signatureInstance(move(sig))
 {
     const FunctionInterpretationData&  functionData = FunctionInterpretationHelper::getSignature(signatureInstance.declaration);
 
     std::set<size_t> argumentsActual;
     for (size_t no=0, size=functionData.signature.size(); no < size; ++no){
         if (functionData.signature.at(no) != INTR_ONLY){
             argumentsActual.insert(no);
         }
     }
 
     functionUnit = new PIFunctionUnit(signatureInstance.declaration, move(argumentsActual), id, target->pass);
     CodeScope* entry = signatureInstance.declaration->__entry;
     auto entryUnit = Decorators<CachedScopeDecoratorTag>::getInterface<>(functionUnit->getEntry());
     InterpretationScope* entryIntrp = InterpretationFunction::getScope(entry);
 
     for(size_t no=0, sigNo=0, size = entry->__bindings.size(); no < size; ++no){
         if (functionData.signature.at(no) == INTR_ONLY){
             entryIntrp->overrideBinding(signatureInstance.bindings[sigNo], entry->__bindings[no]);
 
             VNameId argId = entry->__identifiers.at(entry->__bindings[no]);
             Symbol argSymbol{ScopedSymbol{argId, versions::VERSION_NONE}, entry};
             entryUnit->overrideDeclaration(argSymbol, Expression(signatureInstance.bindings[sigNo]));
             ++sigNo;
         }
     }
 }
 
 llvm::Function*
 PIFunction::compile(){
     llvm::Function* raw = functionUnit->compile();
 
     return raw;
 }
 
 bool operator<(const PIFSignature& lhs, const PIFSignature& rhs){
     if (lhs.declaration.id() != rhs.declaration.id()) {
         return lhs.declaration.id() < rhs.declaration.id();
     }
 
     return lhs.bindings < rhs.bindings;
 }
 
 bool operator<(const PIFSignature& lhs, PIFunction* const rhs){
     return lhs < rhs->signatureInstance;
 }
 
 bool operator<(PIFunction* const lhs, const PIFSignature& rhs){
     return lhs->signatureInstance < rhs;
 }
 
 }}
 
 /** \class xreate::interpretation::InterpretationFunction
  *
  * Holds list of xreate::interpretation::InterpretationScope 's focused on interpretation of individual code scopes
  *
  * There is particulat subclass  PIFunction intended to represent partially interpreted functions
  *\sa TargetInterpretation, [Interpretation Concept](/w/concepts/dfa)
  */
 /** \class xreate::interpretation::TargetInterpretation
  *
  * Executed during compilation and intented to preprocess eligible parts of code.
  * Established on [Targets Infrastructure](\ref compilation::Target)
  *
  * Holds list of InterpretationFunction / PIFunction to represent interpretation process for individual functions
  *
  * In order to be activated during compilation process there is
  *  InterpretationScopeDecorator implementation of ICodeScopeUnit
  * \sa InterpretationPass, compilation::Target, [Interpretation Concept](/w/concepts/dfa)
  *
  */
\ No newline at end of file
diff --git a/cpp/src/compilation/targetinterpretation.h b/cpp/src/compilation/targetinterpretation.h
index 99a29d7..567bf92 100644
--- a/cpp/src/compilation/targetinterpretation.h
+++ b/cpp/src/compilation/targetinterpretation.h
@@ -1,139 +1,139 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * File:   targetstatic.h
  * Author: pgess  <v.melnychenko@xreate.org>
  *
  * Created on July 2, 2016, 1:25 PM
  */
 
 #ifndef TARGETSTATIC_H
 #define TARGETSTATIC_H
 
 #include "ast.h"
 #include "pass/compilepass.h"
 #include "compilation/targets.h"
 #include "pass/interpretationpass.h"
 #include "clasplayer.h"
 
 namespace xreate{ namespace interpretation{
     class TargetInterpretation;
     class InterpretationScope;
     class InterpretationFunction;
 }}
 
 namespace xreate{ namespace compilation{
     template <>
     struct TargetInfo<interpretation::TargetInterpretation> {
         typedef Expression Result;
         typedef interpretation::InterpretationScope Scope;
         typedef interpretation::InterpretationFunction Function;
     };    
 }}
 
 namespace xreate{ namespace interpretation{
     
     /** \brief Encapsulates interpretation of a single Code Scope */
 class InterpretationScope: public  compilation::Scope<TargetInterpretation>{
     typedef Scope<TargetInterpretation> Parent;
     
 public:
-    InterpretationScope(CodeScope* scope, compilation::Function<TargetInterpretation>* f): Parent(scope, f) {}
+    InterpretationScope(const CodeScope* scope, compilation::Function<TargetInterpretation>* f): Parent(scope, f) {}
     Expression process(const Expression& expression) override;
     
     llvm::Value* compile(const Expression& expression, const compilation::Context& context);
     
 private:
     llvm::Value* compileHybrid(const InterpretationOperator& op, const Expression& expression, const compilation::Context& context);
     //llvm::Value* compilePartialFnCall(const Expression& expression, const Context& context);
     
     CodeScope* processOperatorIf(const Expression& expression);
     CodeScope* processOperatorSwitch(const Expression& expression);
     CodeScope* processOperatorSwitchVariant(const Expression& expression);
 };
 
 /** \brief Encapsulates interpretation of a single %Function */
 class InterpretationFunction: public compilation::Function<TargetInterpretation>{
 public:
     InterpretationFunction(const ManagedFnPtr& function, compilation::Target<TargetInterpretation>* target);
     Expression process(const std::vector<Expression>& args);
 };
 
 /** \brief Signature of a partially interpreted function */
 struct PIFSignature{
     ManagedFnPtr declaration;
     std::vector<Expression> bindings;
 };
 
 class PIFunctionUnit;
 
 /** \brief Partially interpreted function */
 class PIFunction: public InterpretationFunction{
 public:
     PIFunctionUnit* functionUnit;
     PIFSignature signatureInstance;
     
     PIFunction(PIFSignature&& sig, size_t id, TargetInterpretation* target);
     llvm::Function* compile();
 };
 
 bool operator<(const PIFSignature& lhs, PIFunction* const rhs);
 bool operator<(PIFunction* const lhs, const PIFSignature& rhs);
 
 /** \brief Encapsulates actual [Interpretation](/w/concepts/dfa) based on InterpretationPass analysis results */
 class TargetInterpretation: public compilation::Target<TargetInterpretation>{
 public:    
     TargetInterpretation(AST* root, CompilePass* passCompilation): Target<TargetInterpretation>(root), pass(passCompilation){}
 
         //target:
 public:
    InterpretationFunction* getFunction(compilation::IFunctionUnit* unit);
    PIFunction* getFunction(PIFSignature&& sig);
    
 private:
    std::map<PIFSignature, PIFunction*> __pifunctions;
    std::map<compilation::IFunctionUnit*, InterpretationFunction*> __dictFunctionsByUnit;
 
         //self:
 public:
     CompilePass* pass;
     llvm::Value* compile(const Expression& expression, const compilation::Context& ctx);
 private:
     InterpretationScope* transformContext(const compilation::Context& c);
 };
 
 /**\brief Interpretation-aware Code Scope decorator
  * \extends xreate::compilation::ICodeScopeUnit
  */
 template<class Parent>
 class InterpretationScopeDecorator: public Parent{
 public:
-    InterpretationScopeDecorator(CodeScope* codeScope, compilation::IFunctionUnit* f, CompilePass* compilePass): Parent(codeScope, f, compilePass){}
+    InterpretationScopeDecorator(const CodeScope* const codeScope, compilation::IFunctionUnit* f, CompilePass* compilePass): Parent(codeScope, f, compilePass){}
     
     virtual llvm::Value* process(const Expression& expr, const std::string& hintVarDecl){
         const InterpretationData& data = Attachments::get<InterpretationData>(expr, {ANY, NONE});
         bool flagInterpretationEligible = (data.resolution == INTR_ONLY || data.op != InterpretationOperator::NONE);
 
         if (flagInterpretationEligible){
             compilation::Context ctx{this, this->function, this->pass};
             return Parent::pass->targetInterpretation->compile(expr, ctx);
         }
         
         return Parent::process(expr, hintVarDecl);
     }
 };
 
 /** \brief translates Logic expression(Gringo::Symbol) into Xreate expression to support intrinsic function `query` */
 Expression representAsAnnotation(const Gringo::Symbol& symbol);
 
 }} //end of xreate:: interpretation
 
 #endif /* TARGETSTATIC_H */
 
 
 //transformers: 
 //    template<> 
 //    struct TransformerInfo<TargetInterpretation> {
 //        static const int id = 1;
 //    };
diff --git a/cpp/src/compilation/targets.h b/cpp/src/compilation/targets.h
index 5c39425..1b86b31 100644
--- a/cpp/src/compilation/targets.h
+++ b/cpp/src/compilation/targets.h
@@ -1,201 +1,201 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * File:   targetabstract.h
  * Author: pgess <v.melnychenko@xreate.org>
  *
  * Created on July 2, 2016, 1:25 PM
  */
 
 /**
  * \file    
  * \brief   Compilation targets infrastructure 
  */
 
 
 #ifndef TARGETABSTRACT_H
 #define TARGETABSTRACT_H
 #include "ast.h"
 
 #include <boost/optional.hpp>
 #include <map>
 
 namespace xreate{ namespace compilation {
     
 template <typename ConcreteTarget> 
 struct TargetInfo{
     //typedef Result 
     //typedef Function
     //typedef Scope 
 };
     
 template<typename ConcreteTarget>
 class Function;
 
 template<typename ConcreteTarget>
 class Target;
 
 template<typename ConcreteTarget>
 class Scope{
     typedef typename TargetInfo<ConcreteTarget>::Scope Self;
     
 public:
-    CodeScope* scope;
+    const CodeScope* scope;
     
     typename TargetInfo<ConcreteTarget>::Result
     processSymbol(const Symbol& s){
-        CodeScope* scope = s.scope;
+        const CodeScope* scope = s.scope;
         Self* self = function->getScope(scope);
 
         if (self->__bindings.count(s.identifier))     {
             return self->__bindings[s.identifier];
         }
 
         const Expression& declaration = CodeScope::getDefinition(s, true);
         if (!declaration.isDefined()){
             assert(false); //for bindings there should be result already
         }
         
         return self->__bindings[s.identifier] = self->process(declaration);
     }
     
     typename TargetInfo<ConcreteTarget>::Result
     processScope() {
         if (raw) return *raw;
 
         raw = process(scope->getBody());
         return *raw;
     }
     
 //    typename TargetInfo<ConcreteTarget>::Result
 //    processFunction(typename TargetInfo<ConcreteTarget>::Function* fnRemote, const std::vector<typename TargetInfo<ConcreteTarget>::Result>& args){
 //        Scope<ConcreteTarget> scopeRemote = fnRemote->getScope(fnRemote->__function->__entry);
 //        
 //        if (scopeRemote->raw){
 //            return scopeRemote->raw;
 //        }
 //        
 //        return fnRemote->process(args);
 //    }
     
     virtual typename TargetInfo<ConcreteTarget>::Result
     process(const Expression& expression)=0;    
     
-    Scope(CodeScope* codeScope, Function<ConcreteTarget>* f)
+    Scope(const CodeScope* codeScope, Function<ConcreteTarget>* f)
             : scope(codeScope), function(f)  {}
     
     virtual ~Scope(){}
 
     void 
     overrideBinding(typename TargetInfo<ConcreteTarget>::Result arg, const std::string& name){
         assert(scope->__identifiers.count(name));
         
         ScopedSymbol id{scope->__identifiers.at(name), versions::VERSION_NONE};
         __bindings[id] = arg;
         
         //reset the result if any:
         raw.reset();
     }
     
     void registerChildScope(std::shared_ptr<Self> scope){
         __childScopes.push_back(scope);
     }
 
     void reset(){
         __bindings.clear();
         __childScopes.clear();
         raw.reset();
     }
     
 protected:
     Function<ConcreteTarget>* function=0;
     std::map<ScopedSymbol, typename TargetInfo<ConcreteTarget>::Result> __bindings;
     std::list<std::shared_ptr<Self>> __childScopes;
     typename boost::optional<typename TargetInfo<ConcreteTarget>::Result> raw;
 };
 
 template<typename ConcreteTarget>
 class Function{
     typedef typename TargetInfo<ConcreteTarget>::Result Result;
     typedef typename TargetInfo<ConcreteTarget>::Scope ConcreteScope;
     
 public:
     Function(const ManagedFnPtr& function, Target<ConcreteTarget>* target)
         : man(target), __function(function)  {}
         
 	virtual ~Function(){};
         
     ConcreteScope*
-    getScope(CodeScope* scope){
+    getScope(const CodeScope* const scope){
         if (__scopes.count(scope)) {
             auto result = __scopes.at(scope).lock();
             
             if (result){
                 return result.get();
             }
         }
 
         std::shared_ptr<ConcreteScope> unit(new ConcreteScope(scope, this));
             
         if (scope->__parent != nullptr){
             getScope(scope->__parent)->registerChildScope(unit);
 
         } else {
             assert(!__entryScope);
             __entryScope = unit;
         }
 
         if (!__scopes.emplace(scope, unit).second){
             __scopes[scope] = unit;
         }
         
         return unit.get();
     }
     
     virtual Result
     process(const std::vector<Result>& args)=0;
     
     Target<ConcreteTarget>* man=0;
     ManagedFnPtr __function;
 
 protected:
-    std::map<CodeScope*, std::weak_ptr<ConcreteScope>> __scopes;
+    std::map<const CodeScope*, std::weak_ptr<ConcreteScope>> __scopes;
     std::shared_ptr<ConcreteScope> __entryScope;
 };
 
 /** \brief Similar to xreate::IPass */
 template<typename ConcreteTarget>
 class Target {
     typedef typename TargetInfo<ConcreteTarget>::Function ConcreteFunction;
     
     public:
         Target(AST* root): ast(root){}
         
         ConcreteFunction*
         getFunction(const ManagedFnPtr& function){
             unsigned int id = function.id();
 
             if (!__functions.count(id)){
                 ConcreteFunction* unit = new ConcreteFunction(function, this);
                 __functions.emplace(id, unit);
                 return unit;
             }
 
             return __functions.at(id);
         }
         
         AST* ast;
         virtual ~Target(){
             for (const auto& entry: __functions){
                 delete entry.second;
             }
         }
         
     protected:
         std::map<unsigned int, ConcreteFunction*> __functions;
 };
 
 }}
 
 #endif /* TARGETABSTRACT_H */
diff --git a/cpp/src/compilation/transformations.h b/cpp/src/compilation/transformations.h
index d9c3a67..2dcf8bc 100644
--- a/cpp/src/compilation/transformations.h
+++ b/cpp/src/compilation/transformations.h
@@ -1,116 +1,116 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * File:   transformations.h
  * Author: pgess <v.melnychenko@xreate.org>
  *
  * Created on March 25, 2017, 9:04 PM
  */
 
 #ifndef TRANSFORMATIONS_H
 #define TRANSFORMATIONS_H
 
 #include "pass/compilepass.h"
 
 namespace xreate {    namespace compilation {
 
 template <class TransformerType> 
 struct TransformerInfo {
     //static const unsigned int id = 1; (current vacant id)
 };
     
 class Transformer{
 public:
     virtual llvm::Value* transform(const Expression& expression, llvm::Value* raw, const Context& ctx)=0;
     virtual ~Transformer(){};
 };
 
 class TransformationsManager {
 public:
     std::list<Transformer*> getRelevantTransformers(const Expression& expression);
     
     
     template<class TransformerType>
     void registerTransformer(const std::string& annotation, TransformerType* t){
         const int id = TransformerInfo<TransformerType>::id;
 
         assert(!__transformers.count(id));
         __transformers[id] = t;
         __subscriptions.emplace(annotation, id);
     }
     
     template<class TransformerType>
     void unregisterTransformer(const std::string& annotation, TransformerType* t){
         const unsigned int id = TransformerInfo<TransformerType>::id;
 
         auto range = __subscriptions.equal_range(annotation);
         const auto entry = make_pair(annotation, id);
         __subscriptions.erase(std::find_if(range.first, range.second, [id](const auto& el){return el.second == id;}));
         __transformers.erase(id);
     }
     
     template<class TransformerType>
     TransformerType* update(TransformerType* newInstance){
         const int id = TransformerInfo<TransformerType>::id;
         
         Transformer* oldInstance = __transformers[id];
         __transformers[id] = newInstance;
         
         return static_cast<TransformerType*>(oldInstance);
     }
     
     template<class TransformerType>
     bool exists(){
         const int id = TransformerInfo<TransformerType>::id;
         
         return __transformers.count(id);
     }
             
     template <class TransformerType>
     TransformerType* get(){
         const int id = TransformerInfo<TransformerType>::id;
         return static_cast<TransformerType*>(__transformers.at(id));
     }    
     
 private:
     std::map<unsigned int, Transformer*> __transformers;
     std::multimap<std::string, unsigned int> __subscriptions;
 };
 
 /**\brief Provides custom transformations during Code Scope compilation
  * \extends xreate::compilation::ICodeScopeUnit
  */
 template <class Parent>
 class TransformationsScopeDecorator: public Transformer, public Parent {
                 // SCOPE DECORATOR PART
 public:    
-    TransformationsScopeDecorator(CodeScope* codeScope, IFunctionUnit* f, CompilePass* compilePass)
+    TransformationsScopeDecorator(const CodeScope* const codeScope, IFunctionUnit* f, CompilePass* compilePass)
         : Parent(codeScope, f, compilePass){}
     
     virtual llvm::Value* 
     process(const Expression& expr, const std::string& hintVarDecl=""){
         llvm::Value* result = Parent::process(expr, hintVarDecl);
         return transform(expr, result, Context{this, Parent::function, Parent::pass});
     }
   
                 // TRANSFORMER PART
 public:
     virtual llvm::Value* 
     transform(const Expression& expression, llvm::Value* raw, const Context& ctx) {
         llvm::Value* result = raw;
         TransformationsManager* man = Parent::pass->managerTransformations;
         
         if (expression.tags.size())
         for (Transformer* handler: man->getRelevantTransformers(expression)){
             result = handler->transform(expression, result, ctx);
         }
         
         return result;
     }
 };
     
 } } 
 
 #endif /* TRANSFORMATIONS_H */
 
diff --git a/cpp/src/compilation/versions.h b/cpp/src/compilation/versions.h
index d63d03c..c448bde 100644
--- a/cpp/src/compilation/versions.h
+++ b/cpp/src/compilation/versions.h
@@ -1,153 +1,153 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * versions.cpp
  *
  * Author: pgess <v.melnychenko@xreate.org>
  * Created on January 21, 2017, 1:24 PM
  */
 
 /**
  * \file    
  * \brief   CodeScope's Decorator to support Versions
  */
 
 #include "pass/versionspass.h"
 #include "pass/compilepass.h"
 #include "llvmlayer.h"
 
 namespace xreate {
     class CompilePass;
 
 namespace compilation {
     class ICodeScopeUnit;
     class IFunctionUnit;
 }
 
 namespace versions{
     
 /**\brief Enables compilation of code with versioned variables
  * \details Dictates order of computation determined by VersionsPass
  * \extends xreate::compilation::ICodeScopeUnit
  * \sa VersionsPass, VersionsGraph
  */    
 template<class Parent>
 class VersionsScopeDecorator: public Parent{
     typedef VersionsScopeDecorator<Parent> SELF;
     
 public:
-    VersionsScopeDecorator(CodeScope* codeScope, compilation::IFunctionUnit* f, CompilePass* compilePass): Parent(codeScope, f, compilePass){}
+    VersionsScopeDecorator(const CodeScope* const codeScope, compilation::IFunctionUnit* f, CompilePass* compilePass): Parent(codeScope, f, compilePass){}
 
     virtual llvm::Value* processSymbol(const Symbol& s, std::string hintSymbol=""){
         if (Attachments::exists<VersionImposedDependency>(s)){
             const std::list<Symbol> dependencies = Attachments::get<VersionImposedDependency>(s);
 
             for(const Symbol& symbolDependent: dependencies){
                 processSymbol(symbolDependent);
             }
         }
 
         llvm::Value* result = Parent::processSymbol(s, hintSymbol);
         
         if (s.identifier.version == VERSION_INIT){
             llvm::Value* storage = SELF::processIntrinsicInit(result->getType(), hintSymbol);
             setSymbolStorage(s, storage);
             
             processIntrinsicCopy(result, storage);
             return compilation::ICodeScopeUnit::pass->man->llvm->builder.CreateLoad(storage);
             
         } else if (s.identifier.version != VERSION_NONE){
             Symbol symbolInitVersion = getSymbolInitVersion(s);
             
            llvm::Value* storage = getSymbolStorage(symbolInitVersion);
            processIntrinsicCopy(result, storage);
            
            return compilation::ICodeScopeUnit::pass->man->llvm->builder.CreateLoad(storage);
         }
         
         return result;
     }
     
     llvm::Value* 
     processIntrinsicInit(llvm::Type* typeStorage, const std::string& hintVarDecl=""){
         llvm::IntegerType* tyInt = llvm::Type::getInt32Ty(llvm::getGlobalContext());
         llvm::ConstantInt* constOne = llvm::ConstantInt::get(tyInt, 1, false);
         
         return compilation::ICodeScopeUnit::pass->man->llvm->builder.CreateAlloca(typeStorage, constOne, hintVarDecl);
     }
     
     void
     processIntrinsicCopy(llvm::Value* value, llvm::Value* storage){
         compilation::ICodeScopeUnit::pass->man->llvm->builder.CreateStore(value, storage);
     }
     
 private:
     std::map<Symbol, llvm::Value*> __symbolStorage;
     
         static Symbol
     getSymbolInitVersion(const Symbol& s){
         return Symbol{ScopedSymbol{s.identifier.id, VERSION_INIT}, s.scope};
     }
     
     llvm::Value*
     getSymbolStorage(const Symbol& s){
         return __symbolStorage.at(s);
     }
     
     void setSymbolStorage(const Symbol& s, llvm::Value* storage){
         __symbolStorage[s] = storage;
     }
 
 };
 
 template<class Parent>
 class VersionedFunctionDecorator : public Parent {
 public:
     VersionedFunctionDecorator(ManagedFnPtr f, CompilePass* p)
     : Parent(f, p){}
 
 protected:
     std::vector<llvm::Type*> prepareArguments() {
         std::vector<llvm::Type*>&& arguments = Parent::prepareArguments();
 
         return arguments;
     }
 };
 } }  //end of namespace xreate::versions
 
 //    llvm::Value*
 //    processIntrinsicInitAndCopy(){
 //         
 //    }
 
 //llvm::Value*
 //process(const Expression& expr, const std::string& hintVarDecl){
 //    case Operator::CALL_INTRINSIC: {
 //        enum INRINSIC{INIT, COPY};
 //        
 //        const ExpandedType& typSymbol = pass->man->root->expandType(expr.type);
 //
 //        INTRINSIC op = (INTRINSIC) expr.getValueDouble();
 //
 //        switch (op){
 //            case INIT: {
 //                llvm::Type* typSymbolRaw = l.toLLVMType(typSymbol);
 //                
 //
 //                return storage;
 //            }
 //
 //            case COPY: {
 //                llvm::Type* typSymbolRaw = l.toLLVMType(typSymbol);
 //                llvm::value* valueOriginal = process(expr.getOperands()[0], hintVarDecl);
 //                llvm::Value* storage = l.builder.CreateAlloca(typSymbolRaw, constOne, hintVarDecl);
 //                llvm::Value* valueCopy = l.builder.CreateStore(valueOriginal, storage);
 //
 //                return valueCopy;
 //            }
 //        }
 //        return;
 //    }
 //}
 //};
diff --git a/cpp/src/llvmlayer.cpp b/cpp/src/llvmlayer.cpp
index b00afd2..7490e19 100644
--- a/cpp/src/llvmlayer.cpp
+++ b/cpp/src/llvmlayer.cpp
@@ -1,271 +1,288 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * llvmlayer.cpp
  *
  *      Author: pgess <v.melnychenko@xreate.org>
  */
 
 /**
  * \file    llvmlayer.h
  * \brief   Wrapper over LLVM
  */
 
 #include "ast.h"
 #include "llvmlayer.h"
 #include "ExternLayer.h"
 #include "llvm/ExecutionEngine/ExecutionEngine.h"
 #include "llvm/ExecutionEngine/MCJIT.h"
 #include "llvm/Support/TargetSelect.h"
 #include <iostream>
 #include <cmath>
 
 using namespace llvm;
 using namespace xreate;
 using namespace std;
 
 LLVMLayer::LLVMLayer(AST* root)
     : ast(root), builder(getGlobalContext()) {
     module = new llvm::Module(root->getModuleName(), llvm::getGlobalContext());
     layerExtern = new ExternLayer(this);
     layerExtern->init(root);
 }
 
 void*
 LLVMLayer::getFunctionPointer(llvm::Function* function){
 	uint64_t entryAddr = jit->getFunctionAddress(function->getName().str());
 	return (void*) entryAddr;
 }
 
 void
 LLVMLayer::initJit(){
 	std::string ErrStr;
 	LLVMInitializeNativeTarget();
 	llvm::InitializeNativeTargetAsmPrinter();
 
 	llvm::EngineBuilder builder((std::unique_ptr<llvm::Module>(module)));
 	jit = builder
 		.setEngineKind(llvm::EngineKind::JIT)
 		.setErrorStr(&ErrStr)
 		.setVerifyModules(true)
 		.create();
 }
 
 void
 LLVMLayer::print(){
     llvm::PassManager<llvm::Module> PM;
     PM.addPass(llvm::PrintModulePass(llvm::outs(), "banner"));
     PM.run(*module);
 }
 
 llvm::BasicBlock*
 LLVMLayer::initExceptionBlock(llvm::BasicBlock* blockException){
 	initExceptionsSupport();
 
 	PointerType* tyInt8P = PointerType::getInt8PtrTy(llvm::getGlobalContext());
     Value* nullInt8P = llvm::ConstantPointerNull::get(tyInt8P);
 
 
 	builder.SetInsertPoint(blockException);
 	llvm::Function* fAllocate = module->getFunction("__cxa_allocate_exception");
 	llvm::Function* fThrow = module->getFunction("__cxa_throw");
 
 	auto exception = builder.CreateCall(fAllocate, ConstantInt::get(IntegerType::getInt64Ty(getGlobalContext()), 4));
 	vector<Value*> throwParams{exception, nullInt8P, nullInt8P};
 	builder.CreateCall(fThrow, ArrayRef<Value*>(throwParams));
 	builder.CreateUnreachable();
 
 	return blockException;
 }
 
 void
 LLVMLayer::moveToGarbage(void *o)
 {
     __garbage.push_back(o);
 }
 
 llvm::Type*
 LLVMLayer::
 toLLVMType(const ExpandedType& ty) const {
 	std::map<int, llvm::StructType*> empty;
 	return toLLVMType(ty, empty);
 }
 
 llvm::Type*
 LLVMLayer::
 toLLVMType(const ExpandedType& ty, std::map<int, llvm::StructType*>& conjuctions) const
 {
     TypeAnnotation t = ty;
     switch (t.__operator)
     {
         case TypeOperator::ARRAY:
         {
             assert(t.__operands.size()==1);
 
             TypeAnnotation elTy = t.__operands.at(0);
             return llvm::ArrayType::get(toLLVMType(ExpandedType(move(elTy)), conjuctions), t.__size);
         }
 
         case TypeOperator::STRUCT:
         {
             assert(t.__operands.size());
 
             std::vector<llvm::Type*> pack_;
             pack_.reserve(t.__operands.size());
 
             std::transform(t.__operands.begin(), t.__operands.end(), std::inserter(pack_, pack_.end()),
 			   [this, &conjuctions](const TypeAnnotation& t){
 				   return toLLVMType(ExpandedType(TypeAnnotation(t)), conjuctions);
 			   });
 
             llvm::ArrayRef<llvm::Type*> pack(pack_);
 
             			//process recursive types:
             if (conjuctions.count(t.conjuctionId)) {
             	auto result = conjuctions[t.conjuctionId];
             	result->setBody(pack, false);
 
             	return result;
             }
 
             return llvm::StructType::get(llvm::getGlobalContext(), pack, false);
         };
 
         case TypeOperator::LINK: {
         	llvm::StructType* conjuction = llvm::StructType::create(llvm::getGlobalContext());
         	int id = t.conjuctionId;
 
         	conjuctions.emplace(id, conjuction);
         	return conjuction;
         };
 
         case TypeOperator::CALL:
         {
             assert(false);
         };
 
         case TypeOperator::CUSTOM:
         {
             //Look in extern types
-
             clang::QualType qt = layerExtern->lookupType(t.__valueCustom);
             return layerExtern->toLLVMType(qt);
         };
 
         case TypeOperator::VARIANT: {
-        	int size = t.fields.size();
-        	assert(size);
+                /*  Variant Type Layout:
+                *   struct {
+                *       id: i8,       Holds stored variant id
+                *       storage:      type of biggest variant
+                *   }
+                */
+            uint64_t sizeStorage=0;
+            llvm::Type* typStorageRaw = llvm::Type::getVoidTy(llvm::getGlobalContext());
+            for(const TypeAnnotation& subtype: t.__operands){
+                llvm::Type* subtypeRaw = toLLVMType(ExpandedType(subtype), conjuctions);
+
+                uint64_t sizeSubtype = module->getDataLayout().getTypeStoreSize(subtypeRaw);
+                if (sizeSubtype > sizeStorage){
+                    sizeStorage = sizeSubtype;
+                    typStorageRaw = subtypeRaw;
+                }
+            }
+
+            std::array<llvm::Type*, 2> layout;
+            layout[0] = llvm::Type::getInt8Ty(llvm::getGlobalContext()); //id
+            layout[1] = typStorageRaw; //storage
 
-        	int bitcount = ceil(log2(size));
-        	return llvm::Type::getIntNTy(llvm::getGlobalContext(), bitcount);
+            return llvm::StructType::get(llvm::getGlobalContext(), llvm::ArrayRef<llvm::Type*>(layout.begin(), layout.end()));
         }
 
         case TypeOperator::NONE: {
             switch (t.__value) {
                 case TypePrimitive::I32:
                 case TypePrimitive::Int:
                 case TypePrimitive::Num:
                     return llvm::Type::getInt32Ty(llvm::getGlobalContext());
 
                 case TypePrimitive::Bool:
                     return llvm::Type::getInt1Ty(llvm::getGlobalContext());
 
                 case TypePrimitive::I8:
                     return llvm::Type::getInt8Ty(llvm::getGlobalContext());
 
                 case TypePrimitive::I64:
                     return llvm::Type::getInt64Ty(llvm::getGlobalContext());
 
                 case TypePrimitive::Float:
                     return llvm::Type::getDoubleTy(llvm::getGlobalContext());
 
                 case TypePrimitive::String:
                     return llvm::Type::getInt8PtrTy(llvm::getGlobalContext());
 
                 default:
                     assert(false);
             }
         }
 
         default:
             assert(false);
     }
 
     assert(false);
     return  nullptr;
 }
 
 void
 LLVMLayer::initExceptionsSupport(){
 	Type* typInt8Ptr = PointerType::get(IntegerType::get(module->getContext(), 8), 0);
 
 	if (!module->getFunction("__cxa_throw")) {
 		std::vector<Type*>	fThrowSignature{typInt8Ptr, typInt8Ptr, typInt8Ptr};
 
 		 FunctionType* tyFThrow = FunctionType::get(
 		  /*Result=*/Type::getVoidTy(module->getContext()),
 		  /*Params=*/fThrowSignature,
 		  /*isVarArg=*/false);
 
 		llvm::Function::Create(
 	 /*Type=*/tyFThrow,
 	 /*Linkage=*/GlobalValue::ExternalLinkage,
 	 /*Name=*/"__cxa_throw", module); // (external, no body)
 	}
 
 	if (!module->getFunction("__cxa_allocate_exception")) {
 		 std::vector<Type*>fAllocateSignature{IntegerType::get(module->getContext(), 64)};
 
 		 FunctionType* tyFAllocate = FunctionType::get(
 		  /*Result=*/typInt8Ptr,
 		  /*Params=*/fAllocateSignature,
 		  /*isVarArg=*/false);
 
 		llvm::Function::Create(
 	 /*Type=*/tyFAllocate,
 	 /*Linkage=*/GlobalValue::ExternalLinkage,
 	 /*Name=*/"__cxa_allocate_exception", module); // (external, no body)
 	}
 }
 
 bool TypeUtils::isStruct(const ExpandedType& ty){
     const TypeAnnotation& t = ty.get();
 
     if (t.__operator==TypeOperator::STRUCT) {
         return true;
     }
 
     if (t.__operator != TypeOperator::CUSTOM) {
         return false;
     }
 
     clang::QualType tqual = llvm->layerExtern->lookupType(t.__valueCustom);
     const clang::Type * raw = tqual.getTypePtr();
 
         // TODO skip ALL the pointers until non-pointer type found
     if (raw->isStructureType()) return true;
     if (!raw->isAnyPointerType()) return false;
 
     clang::QualType pointee = raw->getPointeeType();
     return pointee->isStructureType();
 }
 
 
 bool TypeUtils::isPointer(const ExpandedType &ty) {
     if (ty.get().__operator != TypeOperator::CUSTOM) return false;
 
     clang::QualType qt = llvm->layerExtern->lookupType(ty.get().__valueCustom);
     return llvm->layerExtern->isPointer(qt);
 }
 
 
 std::vector<std::string>
 TypeUtils::getStructFields(const ExpandedType &t) {
     return (t.get().__operator == TypeOperator::STRUCT)
            ? t.get().fields
             : llvm->layerExtern->getStructFields(
                     llvm->layerExtern->lookupType(t.get().__valueCustom));
 }
 
 
diff --git a/cpp/src/pass/abstractpass.h b/cpp/src/pass/abstractpass.h
index 93322d9..a91d829 100644
--- a/cpp/src/pass/abstractpass.h
+++ b/cpp/src/pass/abstractpass.h
@@ -1,206 +1,206 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * Author: pgess <v.melnychenko@xreate.org>
  */
 
 #ifndef ABSTRACTPASS_H
 #define ABSTRACTPASS_H
 #include "ast.h"
 #include "xreatemanager.h"
 
 #include<iostream>
 namespace xreate
 {
     /** \brief Holds current position in %AST while traversing*/
     struct PassContext
     {
-        CodeScope* scope = 0;
+        const CodeScope* scope = 0;
         ManagedFnPtr function;
         ManagedRulePtr rule;
         std::string varDecl;
 
         PassContext()
         {}
 
-        PassContext updateScope(CodeScope* scopeNew) {
+        PassContext updateScope(const CodeScope* scopeNew) {
             PassContext context2{*this};
             context2.scope = scopeNew;
             return context2;
         }
 
         ~PassContext(){}
     };
 
     /** \brief Base class for all passes to inherit */
     class IPass {
     public:
         IPass(PassManager* manager);
         
         /** \brief Executes pass */
         virtual void run()=0;
         
         /** \brief Finalizes pass. Empty by default*/
         virtual void finish();
 
         PassManager* man;
     };
 
     template<class Output>
     Output defaultValue();
     
     template<>
     void defaultValue<void>();
 
     /** \brief Stores processing results for already visited nodes */
     template<class Output>
     class SymbolCache: private std::map<Symbol, Output>{
         public:
             bool isCached(const Symbol& symbol){
                 return this->count(symbol);
             }
 
             Output setCachedValue(const Symbol& symbol, Output&& value){
                 (*this)[symbol] = value;
                 return value;
             }
 
             Output getCachedValue(const  Symbol& symbol){
                 assert(this->count(symbol));
                 return this->at(symbol);
             }
     };
 
     /** \brief Set of already visited nodes */
     template<>
     class SymbolCache<void>: private std::set<Symbol>{
         public:
         bool isCached(const Symbol& symbol){
             bool result = this->count(symbol) > 0;
             return result;
         }
         void setCachedValue(const Symbol& symbol){
             this->insert(symbol);
         }
 
         void getCachedValue(const  Symbol& symbol){
         }
     };
 
 /** \brief Minimal useful IPass implementation*/    
 template<class Output>
 class AbstractPass: public IPass    {
     SymbolCache<Output> __visitedSymbols;
 
 protected:        
     virtual Output processSymbol(const Symbol& symbol, PassContext context, const std::string& hintSymbol=""){
         if (__visitedSymbols.isCached(symbol))
             return __visitedSymbols.getCachedValue(symbol);
 
 
         const Expression& declaration = CodeScope::getDefinition(symbol, true);
         if (declaration.isDefined()){
             PassContext context2 = context.updateScope(symbol.scope);
 
             Output&& result = process(declaration, context2, hintSymbol);
             return __visitedSymbols.setCachedValue(symbol, std::move(result));
         }
 
         return defaultValue<Output>();
     }
 
     Output processExpressionCall(const Expression& expression, PassContext context){
         const std::string &calleeName = expression.getValueString();
         std::list<ManagedFnPtr> callees = man->root->getFunctionSpecializations(calleeName);
         if (callees.size() == 1 && callees.front()){
             return processFnCall(callees.front(), context);
 
         } else {
             for (const ManagedFnPtr& callee: callees){
                 processFnCallUncertain(callee, context);
             }
 
             return defaultValue<Output>();
         }
     }
 
     SymbolCache<Output>& getSymbolCache(){
         return __visitedSymbols;
     }
 
 public:
     AbstractPass(PassManager* manager)
         : IPass(manager){}
 
         /** \brief Processes function invocation instruction */
     virtual Output processFnCall(ManagedFnPtr functionCallee, PassContext context){
         return defaultValue<Output>();
     }
 
         /** \brief Processes function invocation instruction in uncertain cases
          * \details Executed when it's impossible statically determine exact function invocation. 
          *  In this case get executed for all possible candidates 
          */
     virtual void processFnCallUncertain(ManagedFnPtr functionCallee, PassContext context)
     {}
 
     /** \brief Processes Logic Rule */
     virtual void process(ManagedRulePtr rule)
     {}
 
     /** \brief Processes Function */
     virtual Output process(ManagedFnPtr function)
     {
         PassContext context;
         context.function = function;
 
         return process(function->getEntryScope(), context);
     }    
 
     /** \brief Processes single CodeScope */
     virtual Output process(CodeScope* scope, PassContext context, const std::string& hintBlockDecl=""){
         context.scope = scope;
 
         return processSymbol(Symbol{ScopedSymbol::RetSymbol, scope}, context);
     }
     
     //TODO expose Symbol instead of varDecl. Required by DFAPass. 
     /** \brief Processes single Expression */
     virtual Output process(const Expression& expression, PassContext context, const std::string& varDecl=""){
         if (expression.__state == Expression::IDENT){
             assert(context.scope);
             return processSymbol(Attachments::get<IdentifierSymbol>(expression), context, expression.getValueString());
         }
 
         assert(false);
         return defaultValue<Output>();
     }
 
     /** \brief Executes AST traverse */
     void run() {
         ManagedRulePtr rule = man->root->begin<MetaRuleAbstract>();
         while (rule.isValid()) {
             process(rule);
             ++rule;
         }
 
         ManagedFnPtr f = man->root->begin<Function>();
         while (f.isValid()) {
             process(f);
             ++f;
         }
     }
 
 };
 
 template<>
 void
 AbstractPass<void>::processSymbol(const Symbol& symbol, PassContext context, const std::string& hintSymbol);
 
 template<>
 void
 AbstractPass<void>::process(const Expression& expression, PassContext context, const std::string& hintSymbol);
 
 }    
 #endif
diff --git a/cpp/src/pass/cfapass.cpp b/cpp/src/pass/cfapass.cpp
index f231187..a317acd 100644
--- a/cpp/src/pass/cfapass.cpp
+++ b/cpp/src/pass/cfapass.cpp
@@ -1,124 +1,124 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * cfapass.cpp
  *
  *      Author: pgess <v.melnychenko@xreate.org>
  */
 
 /**
  * \file    cfapass.h
  * \brief   Control Flow Analysis(CFA)
  */
 
 #include "cfapass.h"
 #include "analysis/cfagraph.h"
 #include "analysis/DominatorsTreeAnalysisProvider.h"
 
 #include <boost/range/iterator_range_core.hpp>
 
 using namespace std;
 using namespace xreate::cfa;
 
 void
 CFAPass::initSignatures(){
     auto range = man->root->__interfacesData.equal_range(CFA);
     for (auto i = range.first; i!= range.second; ++i){
             __signatures.emplace(i->second.op, i->second);
     }
 }
 
 void CFAPass::run(){
     initSignatures();
 
     return AbstractPass::run();
 }
 
 void
 CFAPass::finish()
 {
     man->clasp->registerReport(__context.graph);
 
     dominators::DominatorsTreeAnalysisProvider* reportDominators = new dominators::DominatorsTreeAnalysisProvider();
     reportDominators->run(man->clasp, __context.graph);
     man->clasp->registerReport(reportDominators);
 
     return AbstractPass::finish();
 }
 
 void
 CFAPass::processFnCall(ManagedFnPtr function, PassContext context)
 {
     ClaspLayer* clasp = man->clasp;
     __context.graph->addCallConnection(clasp->pack(context.scope), function->getName());
 
     return AbstractPass::processFnCall(function, context);
 }
 
 void
 CFAPass::processFnCallUncertain(ManagedFnPtr function, PassContext context){
     ClaspLayer* clasp = man->clasp;
     __context.graph->addCallConnection(clasp->pack(context.scope), function->getName());
 
     return AbstractPass::processFnCallUncertain(function, context);
 }
 
 void
 CFAPass::process(CodeScope* scope, PassContext context, const std::string& hintBlockDecl){
     ClaspLayer* clasp = man->clasp;
 
-    CodeScope* scopeParent = context.scope;
+    const CodeScope* scopeParent = context.scope;
     ScopePacked scopeId = clasp->pack(scope);
 
     if (scopeParent){
             __context.graph->addParentConnection(scopeId, clasp->pack(scopeParent));
     } else {
             __context.graph->addParentConnection(scopeId, context.function->getName());
     }
 
             //TOTEST scope annotations
             //SECTIONTAG context gather scope annotations
     __context.graph->addScopeAnnotations(scopeId, scope->tags);
 
     __context.graph->addContextRules(scopeId, scope->contextRules);
 
     return AbstractPass::process(scope, context, hintBlockDecl);
 }
 
 //TOTEST scope annotations via scheme
 void
 CFAPass::process(const Expression& expression, PassContext context, const std::string& varDecl){
     ClaspLayer* clasp = man->clasp;
 
     if (expression.__state == Expression::COMPOUND){
         Operator  op= expression.op;
 
         if (__signatures.count(op)) {
             assert(expression.blocks.size());
 
             for (const auto& scheme: boost::make_iterator_range(__signatures.equal_range(expression.op))) {
                 __context.graph->addScopeAnnotations(clasp->pack(expression.blocks.front()), scheme.second.getOperands());
             }
         }
     }
 
     return AbstractPass::process(expression, context, varDecl);
 }
 
 void
 CFAPass::process(ManagedFnPtr function)
 {
     __context.graph->addFunctionAnnotations(function->getName(), function->getTags());
     return AbstractPass::process(function);
 }
 
 CFAPass::CFAPass(PassManager* manager)
     : AbstractPass(manager)
       , __context{new CFAGraph(manager->clasp)}
 {}
 
 /**
  * \class xreate::cfa::CFAPass
  * \details Provides CFA, important analysis for reasoning. Iterates over AST and stores collected data in CFAGraph
  */
\ No newline at end of file
diff --git a/cpp/src/pass/compilepass.cpp b/cpp/src/pass/compilepass.cpp
index 66021a2..799683a 100644
--- a/cpp/src/pass/compilepass.cpp
+++ b/cpp/src/pass/compilepass.cpp
@@ -1,827 +1,847 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * Author: pgess <v.melnychenko@xreate.org>
  *
  * compilepass.cpp
  */
 
 /**
  * \file    compilepass.h
  * \brief   Compilation pass
  */
 
 #include "compilepass.h"
 #include "clasplayer.h"
 #include <ast.h>
 #include "llvmlayer.h"
 
 #include "query/containers.h"
 #include "query/context.h"
 #include "compilation/containers.h"
 #include "compilation/latecontextcompiler2.h"
 #include "ExternLayer.h"
 #include "pass/adhocpass.h"
 #include "compilation/targetinterpretation.h"
 #include "pass/versionspass.h"
 #include "compilation/scopedecorators.h"
 #include "compilation/adhocfunctiondecorator.h"
 #include "compilation/operators.h"
 #include "analysis/typeinference.h"
 
 #include <boost/optional.hpp>
 #include <memory>
 #include <iostream>
 
 using namespace std;
 using namespace llvm;
 
 //TODO use Scope<TargetLlvm>
 
     //SECTIONTAG late-context FunctionDecorator
 
 namespace xreate{namespace context{
 
 /** \brief Late Context enabled decorator for IFunctionUnit
  * \extends IFunctionUnit
  */
 template<class Parent>
 class LateContextFunctionDecorator : public Parent {
 public:
     LateContextFunctionDecorator(ManagedFnPtr f, CompilePass* p)
     : Parent(f, p), contextCompiler(this, p) {
     }
 
 protected:
     std::vector<llvm::Type*> prepareArguments() {
         std::vector<llvm::Type*>&& arguments = Parent::prepareArguments();
 
         size_t sizeLateContextDemand = contextCompiler.getFunctionDemandSize();
         if (sizeLateContextDemand) {
             llvm::Type* ty32 = llvm::Type::getInt32Ty(llvm::getGlobalContext());
             llvm::Type* tyDemand = llvm::ArrayType::get(ty32, sizeLateContextDemand);
 
             arguments.push_back(tyDemand);
         }
 
         return arguments;
     }
 
     llvm::Function::arg_iterator prepareBindings() {
         llvm::Function::arg_iterator fargsI = Parent::prepareBindings();
 
         size_t sizeLateContextDemand = contextCompiler.getFunctionDemandSize();
         if (sizeLateContextDemand) {
             fargsI->setName("latecontext");
             contextCompiler.rawContextArgument = &*fargsI;
             ++fargsI;
         }
 
         return fargsI;
     }
 
 public:
     context::LateContextCompiler2 contextCompiler;
 };
 
 }} //end of namespace xreate::context
 
 namespace xreate { namespace compilation{
 
 std::string
 BasicFunctionUnit::prepareName(){
     AST* ast = IFunctionUnit::pass->man->root;
 
     string name = ast->getFunctionSpecializations(IFunctionUnit::function->__name).size() > 1 ?
             IFunctionUnit::function->__name + std::to_string(IFunctionUnit::function.id()) :
             IFunctionUnit::function->__name;
 
     return name;
 }
 
 std::vector<llvm::Type*>
 BasicFunctionUnit::prepareArguments() {
     LLVMLayer* llvm = IFunctionUnit::pass->man->llvm;
     AST* ast = IFunctionUnit::pass->man->root;
     CodeScope* entry = IFunctionUnit::function->__entry;
     std::vector<llvm::Type*> signature;
 
     std::transform(entry->__bindings.begin(), entry->__bindings.end(), std::inserter(signature, signature.end()),
             [llvm, ast, entry](const std::string & arg)->llvm::Type* {
                 assert(entry->__identifiers.count(arg));
 
                 ScopedSymbol argid{entry->__identifiers.at(arg), versions::VERSION_NONE};
                 return llvm->toLLVMType(ast->expandType(entry->__declarations.at(argid).type));
             });
 
     return signature;
 }
 
 llvm::Type*
 BasicFunctionUnit::prepareResult() {
     LLVMLayer* llvm = IFunctionUnit::pass->man->llvm;
     AST* ast = IFunctionUnit::pass->man->root;
     CodeScope* entry = IFunctionUnit::function->__entry;
 
     return llvm->toLLVMType(ast->expandType(entry->__declarations.at(ScopedSymbol::RetSymbol).type));
 }
 
 llvm::Function::arg_iterator
 BasicFunctionUnit::prepareBindings() {
     CodeScope* entry = IFunctionUnit::function->__entry;
     ICodeScopeUnit* entryCompilation = IFunctionUnit::getScopeUnit(entry);
     llvm::Function::arg_iterator fargsI = IFunctionUnit::raw->arg_begin();
 
     for (std::string &arg : entry->__bindings) {
         ScopedSymbol argid{entry->__identifiers[arg], versions::VERSION_NONE};
 
         entryCompilation->bindArg(&*fargsI, argid);
         fargsI->setName(arg);
         ++fargsI;
     }
 
     return fargsI;
 }
 
     //DEBT compiler rigidly depends on exact definition of DefaultFunctionUnit
 typedef context::LateContextFunctionDecorator<
         adhoc::AdhocFunctionDecorator<
         BasicFunctionUnit>> DefaultFunctionUnit;
 
-ICodeScopeUnit::ICodeScopeUnit(CodeScope* codeScope, IFunctionUnit* f, CompilePass* compilePass)
+ICodeScopeUnit::ICodeScopeUnit(const CodeScope* const codeScope, IFunctionUnit* f, CompilePass* compilePass)
 : pass(compilePass), function(f), scope(codeScope) {
 }
 
 llvm::Value*
 CallStatementRaw::operator()(std::vector<llvm::Value *>&& args, const std::string& hintDecl) {
     llvm::Function* calleeInfo = dyn_cast<llvm::Function>(__callee);
 
     if (calleeInfo) {
         auto argsFormal = calleeInfo->args();
 
         int pos = 0;
         //SECTIONTAG types/convert function ret value
         for (auto argFormal = argsFormal.begin(); argFormal != argsFormal.end(); ++argFormal, ++pos) {
             args[pos] = typeinference::doAutomaticTypeConversion(args[pos], argFormal->getType(), llvm->builder);
         }
     }
 
     return llvm->builder.CreateCall(__calleeTy, __callee, args, hintDecl);
 }
 
     //DESABLEDFEATURE implement inlining
 class CallStatementInline : public ICallStatement {
 public:
     CallStatementInline(IFunctionUnit* caller, IFunctionUnit* callee, LLVMLayer* l)
     : __caller(caller), __callee(callee), llvm(l) {
     }
 
     llvm::Value* operator()(std::vector<llvm::Value *>&& args, const std::string& hintDecl) {
         //TOTEST inlining
         //            CodeScopeUnit* entryCompilation = outer->getScopeUnit(function->__entry);
         //            for(int i=0, size = args.size(); i<size; ++i) {
         //                entryCompilation->bindArg(args.at(i), string(entryCompilation->scope->__bindings.at(i)));
         //            }
         //
         //
         //            return entryCompilation->compile();
 
         return nullptr;
     }
 
 private:
     IFunctionUnit* __caller;
     IFunctionUnit* __callee;
     LLVMLayer* llvm;
 
     bool isInline() {
         // Symbol ret = Symbol{0, function->__entry};
         // bool flagOnTheFly = SymbolAttachments::get<IsImplementationOnTheFly>(ret, false);
         //TODO consider inlining
         return false;
     }
 };
 
-BasicCodeScopeUnit::BasicCodeScopeUnit(CodeScope* codeScope, IFunctionUnit* f, CompilePass* compilePass)
+BasicCodeScopeUnit::BasicCodeScopeUnit(const CodeScope* const codeScope, IFunctionUnit* f, CompilePass* compilePass)
 : ICodeScopeUnit(codeScope, f, compilePass) {
 }
 
 llvm::Value*
 BasicCodeScopeUnit::processSymbol(const Symbol& s, std::string hintRetVar) {
     Expression declaration = CodeScope::getDefinition(s);
-    CodeScope* scope = s.scope;
+    const CodeScope* scope = s.scope;
     ICodeScopeUnit* self = ICodeScopeUnit::function->getScopeUnit(scope);
 
     return self->process(declaration, hintRetVar);
 }
 
 //TASK Isolate out context functionalty in decorator
 //TOTEST static late context decisions
 //TOTEST dynamic late context decisions
 ICallStatement*
 BasicCodeScopeUnit::findFunction(const Expression& opCall) {
     const std::string& calleeName = opCall.getValueString();
     LLVMLayer* llvm = pass->man->llvm;
     ClaspLayer* clasp = pass->man->clasp;
     DefaultFunctionUnit* function = dynamic_cast<DefaultFunctionUnit*> (this->function);
     context::ContextQuery* queryContext = pass->queryContext;
 
     const std::list<ManagedFnPtr>& specializations = pass->man->root->getFunctionSpecializations(calleeName);
 
     //if no specializations registered - check external function
     if (specializations.size() == 0) {
         llvm::Function* external = llvm->layerExtern->lookupFunction(calleeName);
 
         llvm::outs() << "Debug/External function: " << calleeName;
         external->getType()->print(llvm::outs(), true);
         llvm::outs() << "\n";
 
         return new CallStatementRaw(external, llvm);
     }
 
     //no decisions required
     if (specializations.size() == 1) {
         if (!specializations.front()->guardContext.isValid()) {
             return new CallStatementRaw(pass->getFunctionUnit(specializations.front())->compile(), llvm);
         }
     }
 
     //TODO move dictSpecialization over to a separate function in order to perform cache, etc.
     //prepare specializations dictionary
     std::map<Expression, ManagedFnPtr> dictSpecializations;
 
     boost::optional<ManagedFnPtr> variantDefault;
     boost::optional<ManagedFnPtr> variant;
 
     for (const ManagedFnPtr& f : specializations) {
         const Expression& guard = f->guardContext;
 
         //default case:
         if (!guard.isValid()) {
             variantDefault = f;
             continue;
         }
 
         assert(dictSpecializations.emplace(guard, f).second && "Found several identical specializations");
     }
 
     //check static context
     ScopePacked scopeCaller = clasp->pack(this->scope);
     const string atomSpecialization = "specialization";
     const Expression topicSpecialization(Operator::CALL,{(Atom<Identifier_t>(string(atomSpecialization))),
         Expression(Operator::CALL,
         {Atom<Identifier_t>(string(calleeName))}),
         Atom<Number_t>(scopeCaller)});
 
     const context::Decisions& decisions = queryContext->getFinalDecisions(scopeCaller);
     if (decisions.count(topicSpecialization)) {
         variant = dictSpecializations.at(decisions.at(topicSpecialization));
     }
 
     //TODO check only demand for this particular topic.
     size_t sizeDemand = function->contextCompiler.getFunctionDemandSize();
 
     //decision made if static context found or no late context exists(and there is default variant)
     bool flagHasStaticDecision = variant || (variantDefault && !sizeDemand);
 
     //if no late context exists
     if (flagHasStaticDecision) {
         IFunctionUnit* calleeUnit = pass->getFunctionUnit(variant ? *variant : *variantDefault);
 
         //inlining possible based on static decision only
         //        if (calleeUnit->isInline()) {
         //            return new CallStatementInline(function, calleeUnit);
         //        }
 
         return new CallStatementRaw(calleeUnit->compile(), llvm);
     }
 
     //require default variant if no static decision made
     assert(variantDefault);
 
     llvm::Function* functionVariantDefault = this->pass->getFunctionUnit(*variantDefault)->compile();
     llvm::Value* resultFn = function->contextCompiler.findFunction(calleeName, functionVariantDefault, scopeCaller);
     llvm::PointerType *resultPTy = cast<llvm::PointerType>(resultFn->getType());
     llvm::FunctionType *resultFTy = cast<llvm::FunctionType>(resultPTy->getElementType());
     return new CallStatementRaw(resultFn, resultFTy, llvm);
 }
 
 
 
 //DISABLEDFEATURE transformations
 //    if (pass->transformations->isAcceptable(expr)){
 //        return pass->transformations->transform(expr, result, ctx);
 //    }
 
 llvm::Value*
 BasicCodeScopeUnit::process(const Expression& expr, const std::string& hintVarDecl) {
 #define DEFAULT(x) (hintVarDecl.empty()? x: hintVarDecl)
     llvm::Value *left;
     llvm::Value *right;
     LLVMLayer& l = *pass->man->llvm;
-    xreate::compilation::Advanced instructions = xreate::compilation::Advanced({this, function, pass});
+    xreate::compilation::AdvancedInstructions instructions = xreate::compilation::AdvancedInstructions({this, function, pass});
 
     switch (expr.op) {
         case Operator::SUB: case Operator::MUL:
         case Operator::DIV: case Operator::EQU: case Operator::LSS:
         case Operator::GTR: case Operator::NE: case Operator::LSE:
         case Operator::GTE:
 
             assert(expr.__state == Expression::COMPOUND);
             assert(expr.operands.size() == 2);
 
             left = process(expr.operands[0]);
             right = process(expr.operands[1]);
 
             //SECTIONTAG types/convert binary operation
             right = typeinference::doAutomaticTypeConversion(right, left->getType(), l.builder);
             break;
 
         default:;
     }
 
     switch (expr.op) {
         case Operator::ADD:
         {
             left = process(expr.operands[0]);
             Context context{this, function, pass};
 
             llvm::Value* resultSU = StructUpdate::add(expr.operands[0], left, expr.operands[1], context, DEFAULT("tmp_add"));
             if (resultSU) return resultSU;
 
             right = process(expr.operands[1]);
 
             llvm::Value* resultAddPA = pointerarithmetic::PointerArithmetic::add(left, right, context, DEFAULT("tmp_add"));
             if (resultAddPA) {
                 return resultAddPA;
             }
 
             return l.builder.CreateAdd(left, right, DEFAULT("tmp_add"));
             break;
         }
 
         case Operator::SUB:
             return l.builder.CreateSub(left, right, DEFAULT("tmp_sub"));
             break;
 
         case Operator::MUL:
             return l.builder.CreateMul(left, right, DEFAULT("tmp_mul"));
             break;
 
         case Operator::DIV:
             return l.builder.CreateSDiv(left, right, DEFAULT("tmp_div"));
             break;
 
         case Operator::EQU:
             if (left->getType()->isIntegerTy()) return l.builder.CreateICmpEQ(left, right, DEFAULT("tmp_equ"));
             if (left->getType()->isFloatingPointTy()) return l.builder.CreateFCmpOEQ(left, right, DEFAULT("tmp_equ"));
             break;
 
         case Operator::NE:
             return l.builder.CreateICmpNE(left, right, DEFAULT("tmp_ne"));
             break;
 
         case Operator::LSS:
             return l.builder.CreateICmpSLT(left, right, DEFAULT("tmp_lss"));
             break;
 
         case Operator::LSE:
             return l.builder.CreateICmpSLE(left, right, DEFAULT("tmp_lse"));
             break;
 
         case Operator::GTR:
             return l.builder.CreateICmpSGT(left, right, DEFAULT("tmp_gtr"));
             break;
 
         case Operator::GTE:
             return l.builder.CreateICmpSGE(left, right, DEFAULT("tmp_gte"));
             break;
 
         case Operator::NEG:
             left = process(expr.operands[0]);
             return l.builder.CreateNeg(left, DEFAULT("tmp_neg"));
             break;
 
         case Operator::CALL:
         {
             assert(expr.__state == Expression::COMPOUND);
             shared_ptr<ICallStatement> callee(findFunction(expr));
             const std::string& nameCallee = expr.getValueString();
 
             //prepare arguments
             std::vector<llvm::Value *> args;
             args.reserve(expr.operands.size());
 
             std::transform(expr.operands.begin(), expr.operands.end(), std::inserter(args, args.end()),
                 [this](const Expression & operand) {
                     return process(operand);
                 }
             );
 
             ScopePacked outerScopeId = pass->man->clasp->pack(this->scope);
 
             //TASK a) refactor CALL/ADHOC/find function
             //SECTIONTAG late-context propagation arg
             size_t calleeDemandSize = pass->queryContext->getFunctionDemand(nameCallee).size();
             if (calleeDemandSize) {
                 DefaultFunctionUnit* function = dynamic_cast<DefaultFunctionUnit*> (this->function);
                 llvm::Value* argLateContext = function->contextCompiler.compileContextArgument(nameCallee, outerScopeId);
                 args.push_back(argLateContext);
             }
 
             return (*callee)(move(args), DEFAULT("res_" + nameCallee));
         }
 
         case Operator::IF:
         {
             return instructions.compileIf(expr, DEFAULT("tmp_if"));
         }
 
         case Operator::SWITCH:
         {
             return instructions.compileSwitch(expr, DEFAULT("tmp_switch"));
         }
 
         case Operator::LOOP_CONTEXT:
         {
             assert(false);
             return nullptr;
             //return instructions.compileLoopContext(expr, DEFAULT("tmp_loop"));
         }
 
         case Operator::LOGIC_AND:
         {
             assert(expr.operands.size() == 1);
             return process(expr.operands[0]);
         }
 
         case Operator::LIST:
         {
             return instructions.compileListAsSolidArray(expr, DEFAULT("tmp_list"));
         };
 
         case Operator::LIST_RANGE:
         {
             assert(false); //no compilation phase for a range list
             //  return InstructionList(this).compileConstantArray(expr, l, hintRetVar);
         };
 
         case Operator::LIST_NAMED:
         {
             typedef Expanded<TypeAnnotation> ExpandedType;
 
             ExpandedType tyStructLiteral = l.ast->getType(expr);
 
             const std::vector<string> fieldsFormal = (tyStructLiteral.get().__operator == TypeOperator::CUSTOM) ?
                     l.layerExtern->getStructFields(l.layerExtern->lookupType(tyStructLiteral.get().__valueCustom))
                     : tyStructLiteral.get().fields;
 
             std::map<std::string, size_t> indexFields;
             for (size_t i = 0, size = fieldsFormal.size(); i < size; ++i) {
                 indexFields.emplace(fieldsFormal[i], i);
             }
 
             llvm::StructType* tyLiteralRaw = llvm::cast<llvm::StructType>(l.toLLVMType(tyStructLiteral));
             llvm::Value* record = llvm::UndefValue::get(tyLiteralRaw);
 
             for (size_t i = 0; i < expr.operands.size(); ++i) {
                 const Expression& operand = expr.operands.at(i);
                 unsigned int fieldId = indexFields.at(expr.bindings.at(i));
                 llvm::Value* result = process(operand);
                 assert(result);
                 record = l.builder.CreateInsertValue(record, result, llvm::ArrayRef<unsigned>({fieldId}));
             }
 
             return record;
         };
 
         case Operator::MAP:
         {
             assert(expr.blocks.size());
             return instructions.compileMapSolidOutput(expr, DEFAULT("map"));
         };
 
         case Operator::FOLD:
         {
             return instructions.compileFold(expr, DEFAULT("fold"));
         };
 
         case Operator::FOLD_INF:
         {
             return instructions.compileFoldInf(expr, DEFAULT("fold"));
         };
 
         case Operator::INDEX:
         {
             //TASK allow multiindex compilation
             assert(expr.operands.size() == 2);
             assert(expr.operands[0].__state == Expression::IDENT);
 
             const std::string& hintIdent = expr.operands[0].getValueString();
             Symbol s = Attachments::get<IdentifierSymbol>(expr.operands[0]);
             const ExpandedType& t2 = pass->man->root->getType(expr.operands[0]);
 
             llvm::Value* aggr = processSymbol(s, hintIdent);
 
             switch (t2.get().__operator) {
                 case TypeOperator::STRUCT: case TypeOperator::CUSTOM:
                 {
                     std::string idxField;
                     const Expression& idx = expr.operands.at(1);
                     switch (idx.__state) {
 
                             //named struct field
                         case Expression::STRING:
                             idxField = idx.getValueString();
                             break;
 
                             //anonymous struct field
                         case Expression::NUMBER:
                             idxField = to_string((int) idx.getValueDouble());
                             break;
 
                         default:
                             assert(false && "Wrong index for a struct");
                     }
 
                     return instructions.compileStructIndex(aggr, t2, idxField);
                 };
 
                 case TypeOperator::ARRAY:
                 {
                     std::vector<llvm::Value*> indexes;
                     std::transform(++expr.operands.begin(), expr.operands.end(), std::inserter(indexes, indexes.end()),
                             [this] (const Expression & op) {
                                 return process(op);
                             }
                     );
 
                     return instructions.compileArrayIndex(aggr, indexes, DEFAULT(string("el_") + hintIdent));
                 };
 
                 default:
                     assert(false);
             }
         };
 
             //SECTIONTAG adhoc actual compilation
             //TODO a) make sure that it's correct: function->adhocImplementation built for Entry scope and used in another scope
         case Operator::ADHOC:
         {
             DefaultFunctionUnit* function = dynamic_cast<DefaultFunctionUnit*> (this->function);
             assert(function->adhocImplementation && "Adhoc implementation not found");
             const Expression& comm = adhoc::AdhocExpression(expr).getCommand();
 
             CodeScope* scope = function->adhocImplementation->getCommandImplementation(comm);
             ICodeScopeUnit* unitScope = function->getScopeUnit(scope);
 
             //SECTIONTAG types/convert ADHOC ret convertation
             llvm::Type* resultTy = l.toLLVMType(pass->man->root->expandType(function->adhocImplementation->getResultType()));
             return typeinference::doAutomaticTypeConversion(unitScope->compile(), resultTy, l.builder);
         };
 
         case Operator::CALL_INTRINSIC:
         {
             const std::string op = expr.getValueString();
 
             if (op == "copy") {
                 llvm::Value* result = process(expr.getOperands().at(0));
 
                 auto decoratorVersions = Decorators<VersionsScopeDecoratorTag>::getInterface(this);
                 llvm::Value* storage = decoratorVersions->processIntrinsicInit(result->getType());
                 decoratorVersions->processIntrinsicCopy(result, storage);
 
                 return l.builder.CreateLoad(storage, hintVarDecl);
             }
 
             assert(false && "undefined intrinsic");
         }
 
         case Operator::VARIANT:
         {
-            //TASK Variant compilation to implement
-            assert(false&& "Variant compilation not implemented yet");
-            return nullptr;
-//            const ExpandedType& typVariant = pass->man->root->getType(expr);
-//            llvm::Type* typRaw = l.toLLVMType(typVariant);
-//            int value = expr.getValueDouble();
-//            return llvm::ConstantInt::get(typRaw, value);
+            const ExpandedType& typVariant = pass->man->root->getType(expr);
+            llvm::Type* typVariantRaw = l.toLLVMType(typVariant);
+            llvm::Type* typStorageRaw = llvm::cast<llvm::StructType>(typVariantRaw)->getElementType(1);
+            llvm::Type* typIdRaw = llvm::cast<llvm::StructType>(typVariantRaw)->getElementType(0);
+
+            uint64_t id = expr.getValueDouble();
+            const ExpandedType& subtyp = ExpandedType(typVariant->__operands.at(id));
+            llvm::Type* subtypRaw = l.toLLVMType(subtyp);
+            Attachments::put<TypeInferred>(expr.operands.at(0), subtyp);
+            llvm::Value* subtypValue = process(expr.operands.at(0));
+
+            //reinterpret subtype
+            llvm::Value* addrAsStorage = l.builder.CreateAlloca(typStorageRaw);
+            llvm::Value* addrAsSubtyp =  l.builder.CreateBitOrPointerCast(addrAsStorage, subtypRaw->getPointerTo());
+
+            l.builder.CreateStore(subtypValue, addrAsSubtyp);
+            llvm::Value* storageRaw = l.builder.CreateLoad(typStorageRaw, addrAsStorage);
+
+            llvm::Value* variantRaw = llvm::UndefValue::get(typVariantRaw);
+            variantRaw = l.builder.CreateInsertValue(variantRaw, llvm::ConstantInt::get(typIdRaw, id), llvm::ArrayRef<unsigned>({0}));
+            variantRaw = l.builder.CreateInsertValue(variantRaw, storageRaw, llvm::ArrayRef<unsigned>({1}));
+            return variantRaw;
+        }
+
+        case Operator::SWITCH_VARIANT:
+        {
+            return instructions.compileSwitchVariant(expr, DEFAULT("tmpswitch"));
         }
 
         case Operator::NONE:
             assert(expr.__state != Expression::COMPOUND);
 
             switch (expr.__state) {
                 case Expression::IDENT:
                 {
                     Symbol s = Attachments::get<IdentifierSymbol>(expr);
                     return processSymbol(s, expr.getValueString());
                 }
 
                 case Expression::NUMBER:
                 {
                     llvm::Type* typConst;
 
                     if (expr.type.isValid()) {
                         typConst = l.toLLVMType(pass->man->root->getType(expr));
 
                     } else {
                         typConst = llvm::Type::getInt32Ty(llvm::getGlobalContext());
                     }
 
                     int literal = expr.getValueDouble();
                     return llvm::ConstantInt::get(typConst, literal);
                 }
 
                 case Expression::STRING:
                 {
                     return instructions.compileConstantStringAsPChar(expr.getValueString(), DEFAULT("tmp_str"));
                 };
 
                 default:
                 {
                     break;
                 }
             };
 
             break;
 
         default: break;
 
     }
 
     assert(false && "Can't compile expression");
     return 0;
 }
 
 llvm::Value*
 BasicCodeScopeUnit::compile(const std::string& hintBlockDecl) {
     if (!hintBlockDecl.empty()) {
         llvm::BasicBlock *block = llvm::BasicBlock::Create(llvm::getGlobalContext(), hintBlockDecl, function->raw);
         pass->man->llvm->builder.SetInsertPoint(block);
     }
 
     Symbol symbScope = Symbol{ScopedSymbol::RetSymbol, scope};
     return processSymbol(symbScope);
 }
 
 ICodeScopeUnit::~ICodeScopeUnit() {
 }
 
 IFunctionUnit::~IFunctionUnit() {
 }
 
 llvm::Function*
 IFunctionUnit::compile() {
     if (raw != nullptr) return raw;
 
     LLVMLayer* llvm = pass->man->llvm;
     llvm::IRBuilder<>& builder = llvm->builder;
 
     string&& functionName = prepareName();
     std::vector<llvm::Type*>&& types = prepareArguments();
     llvm::Type* expectedResultType = prepareResult();
 
     llvm::FunctionType *ft = llvm::FunctionType::get(expectedResultType, types, false);
     raw = llvm::cast<llvm::Function>(llvm->module->getOrInsertFunction(functionName, ft));
     prepareBindings();
 
     const std::string&blockName = "entry";
     llvm::BasicBlock* blockCurrent = builder.GetInsertBlock();
 
     llvm::Value* result = getScopeUnit(function->__entry)->compile(blockName);
     assert(result);
 
     //SECTIONTAG types/convert function ret value
     builder.CreateRet(typeinference::doAutomaticTypeConversion(result, expectedResultType, llvm->builder));
 
     if (blockCurrent) {
         builder.SetInsertPoint(blockCurrent);
     }
 
     llvm->moveToGarbage(ft);
     return raw;
 }
 
 ICodeScopeUnit*
-IFunctionUnit::getScopeUnit(CodeScope* scope) {
+IFunctionUnit::getScopeUnit(const CodeScope * const scope) {
     if (__scopes.count(scope)) {
         auto result = __scopes.at(scope).lock();
 
         if (result) {
             return result.get();
         }
     }
 
     std::shared_ptr<ICodeScopeUnit> unit(pass->buildCodeScopeUnit(scope, this));
 
     if (scope->__parent != nullptr) {
         auto parentUnit = Decorators<CachedScopeDecoratorTag>::getInterface(getScopeUnit(scope->__parent));
         parentUnit->registerChildScope(unit);
 
     } else {
         __orphanedScopes.push_back(unit);
     }
 
     if (!__scopes.emplace(scope, unit).second) {
         __scopes[scope] = unit;
     }
 
     return unit.get();
 }
 
 ICodeScopeUnit*
 IFunctionUnit::getScopeUnit(ManagedScpPtr scope) {
     return getScopeUnit(&*scope);
 }
 
 ICodeScopeUnit*
 IFunctionUnit::getEntry() {
     return getScopeUnit(function->getEntryScope());
 }
 
 template<>
 compilation::IFunctionUnit*
 CompilePassCustomDecorators<void, void>::buildFunctionUnit(const ManagedFnPtr& function){
     return new DefaultFunctionUnit(function, this);
 }
 
 template<>
 compilation::ICodeScopeUnit*
-CompilePassCustomDecorators<void, void>::buildCodeScopeUnit(CodeScope* scope, IFunctionUnit* function){
+CompilePassCustomDecorators<void, void>::buildCodeScopeUnit(const CodeScope* const scope, IFunctionUnit* function){
     return new DefaultCodeScopeUnit(scope, function, this);
 }
 
 } // emf of compilation
 
 IFunctionUnit*
 CompilePass::getFunctionUnit(const ManagedFnPtr& function) {
     unsigned int id = function.id();
 
     if (!functions.count(id)) {
         IFunctionUnit* unit = buildFunctionUnit(function);
         functions.emplace(id, unit);
         return unit;
     }
 
     return functions.at(id);
 }
 
 void
 CompilePass::run() {
     managerTransformations = new TransformationsManager();
     targetInterpretation = new interpretation::TargetInterpretation(this->man->root, this);
     queryContext = reinterpret_cast<context::ContextQuery*> (man->clasp->getQuery(QueryId::ContextQuery));
 
     //Find out main function;
     ClaspLayer::ModelFragment model = man->clasp->query(Config::get("function-entry"));
     assert(model && "Error: No entry function found");
     assert(model->first != model->second && "Error: Ambiguous entry function");
 
     string nameMain = std::get<0>(ClaspLayer::parse<std::string>(model->first->second));
     IFunctionUnit* unitMain = getFunctionUnit(man->root->findFunction(nameMain));
     entry = unitMain->compile();
 }
 
 llvm::Function*
 CompilePass::getEntryFunction() {
     assert(entry);
     return entry;
 }
 
 void
 CompilePass::prepareQueries(ClaspLayer* clasp) {
     clasp->registerQuery(new containers::Query(), QueryId::ContainersQuery);
     clasp->registerQuery(new context::ContextQuery(), QueryId::ContextQuery);
 
     Attachments::init<PolymorphGuard>();
     clasp->registerQuery(new polymorph::PolymorphQuery(), QueryId::PolymorphQuery);
 }
 } //end of namespace xreate
 
 /**
  * \class xreate::CompilePass
  * \brief Encapsulates all compilation activities
  *
  * xreate::CompilePass iterates over xreate::AST tree and produces executable code fed by data(via xreate::Attachments) gathered by previous passes  as well as data via queries(xreate::IQuery) from xreate:ClaspLayer reasoner.
  * Compilation's done using xreate::LLVMLayer(wrapper over LLVM toolchain) and based on following aspects:
  *   - Containers support. See \ref compilation/containers.h
  *   - Late Conext compilation. See xreate::context::LateContextCompiler2
  *   - Interpretation support. See xreate::interpretation::TargetInterpretation
  *   - Loop saturation support. See xreate::compilation::TransformerSaturation
  *   - External Code access. See xreate::ExternLayer(wrapper over Clang library)
  *
  * \section adaptability_sect Adaptability
  * xreate::CompilePass's architecture provides adaptability by employing:
  *   - %Function Decorators to alter function-level compilation. See xreate::compilation::IFunctionUnit
  *   - Code Block Decorators to alter code block level compilation. See xreate::compilation::ICodeScopeUnit
  *     Default functionality defined by \ref xreate::compilation::DefaultCodeScopeUnit
  *   - Targets to allow more versitile extensions.
  *     Currently only xreate::interpretation::TargetInterpretation  use Targets infrastructure. See xreate::compilation::Target
  *   - %Altering Function invocation. xreate::compilation::ICallStatement
  *
  * Client able to construct compiler with desired decorators using xreate::compilation::CompilePassCustomDecorators.
  * As a handy alias, `CompilePassCustomDecorators<void, void>` constructs default compiler
  *
  */
diff --git a/cpp/src/pass/compilepass.h b/cpp/src/pass/compilepass.h
index 0c16972..7bc170f 100644
--- a/cpp/src/pass/compilepass.h
+++ b/cpp/src/pass/compilepass.h
@@ -1,218 +1,218 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  * 
  * Author: pgess <v.melnychenko@xreate.org>
  * 
  * compilepass.h
  */
 
 #ifndef COMPILEPASS_H
 #define COMPILEPASS_H
 
 #include "abstractpass.h"
 
 #include "llvm/IR/Function.h"
 
 namespace xreate {
     class ClaspLayer;
     class CompilePass;
     class LLVMLayer;
     
     namespace adhoc{
         class AdhocScheme;
     }
     
     namespace context{
         class ContextQuery;
         class LateContextCompiler2;
     }
     
     namespace interpretation{
         class TargetInterpretation;
     }
 }
 
 namespace xreate { namespace compilation {
 
 class ICodeScopeUnit;
 class IFunctionUnit;
 class TransformationsManager;
 
 /** \brief Holds current position in %AST while traversing*/
 struct Context{
     ICodeScopeUnit* scope;
     IFunctionUnit* function;
     CompilePass* pass;
 };
 
 /** \brief Interface to specify custom way of function invocation 
  *  \details Default implementation is xreate::compilation::CallStatementRaw
  */
 class ICallStatement {
 public:
     /** \brief Returns result of custom function invocation for given arguments*/
     virtual llvm::Value* operator() (std::vector<llvm::Value *>&& args, const std::string& hintDecl="") = 0;
 };
 
 /** \brief Default ICallStatement implementation */
 class CallStatementRaw: public ICallStatement{
 public:
     CallStatementRaw(llvm::Function* callee, LLVMLayer* l)
         : __callee(callee), __calleeTy(callee->getFunctionType()), llvm(l) {}
     CallStatementRaw(llvm::Value* callee, llvm::FunctionType* ty, LLVMLayer* l)
         : __callee(callee), __calleeTy(ty), llvm(l) {}
     
     /** \brief Makes type conversions and returns LLVM call statement with given arguments*/
     llvm::Value* operator() (std::vector<llvm::Value *>&& args, const std::string& hintDecl="");
         
 private:
     llvm::Value* __callee;        
     llvm::FunctionType* __calleeTy;
     LLVMLayer* llvm;
 };
 
 /** \brief Interface to allow modification of CodeScope compilation
  *  \details Default implementation defined in xreate::compilation::DefaultCodeScopeUnit
  */
 class ICodeScopeUnit{
 public:
     CompilePass* const pass;
     IFunctionUnit* const function;
-    CodeScope* const scope;
+    const CodeScope* const scope;
     
-    ICodeScopeUnit(CodeScope* codeScope, IFunctionUnit* f, CompilePass* compilePass);
+    ICodeScopeUnit(const CodeScope* const codeScope, IFunctionUnit* f, CompilePass* compilePass);
     virtual ~ICodeScopeUnit();
 
     virtual llvm::Value* compile(const std::string& hintBlockDecl="")=0;
     virtual llvm::Value* processSymbol(const Symbol& s, std::string hintRetVar="")=0;
     virtual llvm::Value* process(const Expression& expr, const std::string& hintVarDecl="")=0;
     
-    virtual void bindArg(llvm::Value* value, std::string&& alias)=0;
+    virtual Symbol bindArg(llvm::Value* value, std::string&& alias)=0;
     virtual void bindArg(llvm::Value* value, const ScopedSymbol& s)=0;
 
 protected:
     virtual ICallStatement* findFunction(const Expression& opCall)=0;
 };
 
 /** \brief Minimal useful ICodeScopeUnit implementation suited for inheritance */
 class BasicCodeScopeUnit: public ICodeScopeUnit{
 public:
-    BasicCodeScopeUnit(CodeScope* codeScope, IFunctionUnit* f, CompilePass* compilePass);
+    BasicCodeScopeUnit(const CodeScope* const codeScope, IFunctionUnit* f, CompilePass* compilePass);
 
     llvm::Value* processSymbol(const Symbol& s, std::string hintRetVar="") override;
     llvm::Value* process(const Expression& expr, const std::string& hintVarDecl="") override;
     llvm::Value* compile(const std::string& hintBlockDecl="") override;
     
 protected:
     ICallStatement* findFunction(const Expression& opCall) override;
 };
 
 /** \brief Interface to specify compilation of %Function */
 class IFunctionUnit{
 public:
    IFunctionUnit(ManagedFnPtr f, CompilePass* p): function(f), pass(p) {}
    virtual ~IFunctionUnit();
 
     llvm::Function* compile();
 
     ICodeScopeUnit* getEntry();
-    ICodeScopeUnit* getScopeUnit(CodeScope* scope);
+    ICodeScopeUnit* getScopeUnit(const CodeScope * const scope);
     ICodeScopeUnit* getScopeUnit(ManagedScpPtr scope);
 
     ManagedFnPtr function;
     llvm::Function* raw = nullptr;
     
 protected:
     CompilePass* pass=nullptr;
     
     virtual std::string prepareName() = 0;
     virtual std::vector<llvm::Type*>  prepareArguments() = 0;
     virtual llvm::Type* prepareResult() = 0;
     virtual llvm::Function::arg_iterator prepareBindings() = 0;
     
 private:
-    std::map<CodeScope*, std::weak_ptr<ICodeScopeUnit>> __scopes;
+    std::map<const CodeScope * const, std::weak_ptr<ICodeScopeUnit>> __scopes;
     std::list<std::shared_ptr<ICodeScopeUnit>> __orphanedScopes;
 };
 
 /** \brief Minimal useful IFunctionUnit implementation suited for inheritance */
 class BasicFunctionUnit: public IFunctionUnit{
 public:
     BasicFunctionUnit(ManagedFnPtr f, CompilePass* p)
     : IFunctionUnit(f, p) {}
 
 protected:
     std::string prepareName() override;
     virtual std::vector<llvm::Type*>  prepareArguments() override;
     virtual llvm::Type* prepareResult() override;
     virtual llvm::Function::arg_iterator prepareBindings() override;
 };
 } // end of namespace compilation
 
 class CompilePass : public AbstractPass<void> {
     friend class context::LateContextCompiler2;
     friend class compilation::BasicCodeScopeUnit;
     friend class compilation::IFunctionUnit;
 
 public:
     compilation::TransformationsManager* managerTransformations;
     interpretation::TargetInterpretation* targetInterpretation;
     
     CompilePass(PassManager* manager): AbstractPass<void>(manager) {}
     /** \brief Executes compilation process */
     void run() override;
     
     /**\brief Returns compiled specified %Function
      * \details Executes function compilation or read cache if it's already done
      */
     compilation::IFunctionUnit* getFunctionUnit(const ManagedFnPtr& function);
     
     /**\brief Returns compiled main(entry) %Function in program */
     llvm::Function* getEntryFunction();
     
     /** \brief Initializes queries required by compiler. See xreate::IQuery, xreate::ClaspLayer */
     static void prepareQueries(ClaspLayer* clasp);
     
     
     
 protected:
     virtual compilation::IFunctionUnit* buildFunctionUnit(const ManagedFnPtr& function)=0;
-    virtual compilation::ICodeScopeUnit* buildCodeScopeUnit(CodeScope* scope, compilation::IFunctionUnit* function)=0;
+    virtual compilation::ICodeScopeUnit* buildCodeScopeUnit(const CodeScope* const scope, compilation::IFunctionUnit* function)=0;
     
 private:
     //TODO free `functions` in destructor
     std::map<unsigned int, compilation::IFunctionUnit*> functions;
     llvm::Function* entry = 0;
 
     context::ContextQuery* queryContext;    
 };
 
 namespace compilation{
 
 /** \brief Constructs compiler with desired %Function and %Code Scope decorators. See adaptability in xreate::CompilePass*/    
 template<class FUNCTION_DECORATOR=void, class SCOPE_DECORATOR=void>
 class CompilePassCustomDecorators: public ::xreate::CompilePass{
 public:
     CompilePassCustomDecorators(PassManager* manager): ::xreate::CompilePass(manager) {}
     
     virtual compilation::IFunctionUnit* buildFunctionUnit(const ManagedFnPtr& function) override{
         return new FUNCTION_DECORATOR(function, this);
     }
     
-    virtual compilation::ICodeScopeUnit* buildCodeScopeUnit(CodeScope* scope, IFunctionUnit* function) override{
+    virtual compilation::ICodeScopeUnit* buildCodeScopeUnit(const CodeScope* const scope, IFunctionUnit* function) override{
         return new SCOPE_DECORATOR(scope, function, this);
     }        
 };
 
 template<>
 compilation::IFunctionUnit* 
 CompilePassCustomDecorators<void, void>::buildFunctionUnit(const ManagedFnPtr& function);
 
 template<>
 compilation::ICodeScopeUnit*
-CompilePassCustomDecorators<void, void>::buildCodeScopeUnit(CodeScope* scope, IFunctionUnit* function);
+CompilePassCustomDecorators<void, void>::buildCodeScopeUnit(const CodeScope* const scope, IFunctionUnit* function);
 
 }} //end of namespace xreate::compilation
 
 #endif // COMPILEPASS_H
diff --git a/cpp/tests/adhoc.cpp b/cpp/tests/adhoc.cpp
index eae5f4a..72a565f 100644
--- a/cpp/tests/adhoc.cpp
+++ b/cpp/tests/adhoc.cpp
@@ -1,196 +1,196 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/
  *
  * adhoc-exceptions.cpp
  *
  *  Created on: Nov 19, 2015
  *      Author: pgess <v.melnychenko@xreate.org>
  */
 
 class Adhoc_pass_Adhoc1_Test;
 #define FRIENDS_ADHOC \
     friend class ::Adhoc_pass_Adhoc1_Test;
 
 
 #include "ast.h"
 #include "xreatemanager.h"
 
 #include "gtest/gtest.h"
 #include <stdio.h>
 #include <memory>
 #include <sstream>
 #include <stdlib.h>
 
 
 #include "pass/adhocpass.h"
 #include "pass/compilepass.h"
 #include "llvmlayer.h"
 
 using namespace xreate;
 using namespace xreate::adhoc;
 using namespace std;
 
 TEST(Adhoc, ast_operatorAdhoc1){
     XreateManager* man = XreateManager::prepare (
     "test = function:: int {\n"
     "   ad hoc exception(nonImplemented)\n"
     "}");
 
-    Expression subject = man->root->findFunction("test")->getEntryScope()->getBody();
+    const Expression& subject = man->root->findFunction("test")->getEntryScope()->getBody();
     ASSERT_EQ(Operator::ADHOC, subject.op);
 
     Expression exception = AdhocExpression(subject).getCommand();
     ASSERT_EQ("exception", exception.getValueString());
 }
 
 TEST(Adhoc, ast_schemeAdhoc1){
     XreateManager* man = XreateManager::prepare (
     "interface(adhoc){\n"
     "		pre function expectNoErrors:: bool {\n"
     "			case (Error)  {false}\n"
     "			case (Success) {true}\n"
     "		}\n"
     "	}");
 
     assert(man->root->__interfacesData.count(ASTInterface::Adhoc));
     Expression adhocData = man->root->__interfacesData.find(ASTInterface::Adhoc)->second;
     ASSERT_EQ(Operator::SWITCH, adhocData.operands[0].op);
 }
 
 TEST(Adhoc, pass_Adhoc1){
     details::tier1::XreateManager* man = details::tier1::XreateManager::prepare (
     "interface(adhoc){\n"
     "   pre function expectNoErrors:: bool {\n"
     "       case (Error)  {false}\n"
     "       case (Success) {true}\n"
     "   }\n"
     "}\n"
 
     "main = function::int; entry {0} \n"
     );
 
     man->analyse();
     AdhocPass* pass = reinterpret_cast<AdhocPass* >(man->getPassById(PassId::AdhocPass));
     EXPECT_TRUE(pass->__schemes.size() > 0);
 
     AdhocScheme* scheme =  pass->__schemes.begin()->second;
     EXPECT_EQ("expectNoErrors", scheme->getName());
 }
 
 TEST(Adhoc, full_1){
     XreateManager* man = XreateManager::prepare (
     "	import raw (\"core/control-context.lp\").\n"
 
     "	interface(adhoc){\n"
     "		pre function expectNoErrors:: bool {\n"
     "			case (error)  {false}\n"
     "			case (success) {true}\n"
     "		}\n"
     "	}\n"
 
     "	test1 = pre function {\n"
     "		context:: expectNoErrors."
     "		ad hoc success\n"
     "	}"
 
     "main = function::bool;entry {\n"
     "			test1()\n"
     "		}");
 
     bool (*main)() = (bool (*)()) man->run();
     bool result = main();
     ASSERT_EQ(true, result);
 }
 
 TEST(Adhoc, full_2){
     XreateManager* man = XreateManager::prepare (
     "	import raw (\"core/control-context.lp\").\n"
 
     "	interface(adhoc){\n"
     "		pre function expectNoErrors:: bool {\n"
     "			case (error)  {false}\n"
     "			case (success) {true}\n"
     "		}\n"
 
     "		pre function expectErrors:: bool {\n"
     "			case (error)  {true}\n"
     "			case (success) {false}\n"
     "		}\n"
 
     "	}\n"
 
     "	test1 = pre function {\n"
     "		context:: expectNoErrors."
     "		ad hoc success\n"
     "	}\n"
 
     "	test2 = pre function {\n"
     "		context:: expectErrors."
     "		ad hoc success\n"
     "	}"
 
     "main = function::bool;entry {\n"
     "   test1() != test2()\n"
     "}");
 
     bool (*main)() = (bool (*)()) man->run();
     bool result = main();
     ASSERT_EQ(true, result);
 }
 
 //TODO adhoc type. FDecl sets wrong type in prefunc case(invalid type))
 TEST(Adhoc, full_contextExpectNoErrrors){
     XreateManager* man = XreateManager::prepare (
     "import raw (\"core/control-context.lp\").\n"
 
     "interface(extern-c){\n"
     "  xml2 = library:: pkgconfig(\"libxml-2.0\").\n"
     "  \n"
     "  include {\n"
     "    xml2 = [\"stdlib.h\"]\n"
     "  }.\n"
     "}"
 
     "interface(adhoc){\n"
     "	pre function expectNoErrors:: bool {\n"
     "		case (error)  {false}\n"
     "		case (success) {true}\n"
     "	}\n"
     "}\n"
 
     "expectErrorCode = pre function(x::int){\n"
     "	if (x==0)::undef {ad hoc success}\n"
     "	else {ad hoc error}\n"
     "}\n"
 
     "main = function::bool; entry {\n"
     "		context:: expectNoErrors."
     "		expectErrorCode(system(\"ls -la\"))\n"
     "}"	);
 
     int (*main)() = (int (*)()) man->run();
     ASSERT_EQ(1, main());
 }
 
 //DEBT Implement compilation of switch adhoc
 TEST(Adhoc, ast_switchAdhoc1){
     XreateManager* man = XreateManager::prepare (
         "test1 = function:: bool {\n"
         "   x = 0. \n"
         "   switch ad hoc (x:: errors)\n"
         "       case (error) {0}\n"
         "	case (success) {1}\n"
         "\n"
         "}"
     );
 
-    Expression eSwitch = man->root->findFunction("test1")->getEntryScope()->getBody();
+    const Expression& eSwitch = man->root->findFunction("test1")->getEntryScope()->getBody();
     EXPECT_EQ(Operator::SWITCH_ADHOC, eSwitch.op);
     EXPECT_EQ(3, eSwitch.operands.size());
 
     EXPECT_EQ(1, eSwitch.tags.size());
     EXPECT_EQ("errors", eSwitch.tags.begin()->first);
 
     Expression eCondition = eSwitch.getOperands()[0];
     EXPECT_EQ("x", eCondition.getValueString());
 }
diff --git a/cpp/tests/compilation.cpp b/cpp/tests/compilation.cpp
index 12377ae..41d6927 100644
--- a/cpp/tests/compilation.cpp
+++ b/cpp/tests/compilation.cpp
@@ -1,104 +1,147 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/
  *
  * compilation.cpp
  *
  *  Created on: -
  *      Author: pgess <v.melnychenko@xreate.org>
  */
 
 #include "xreatemanager.h"
 #include "gtest/gtest.h"
 using namespace xreate;
 //DEBT implement no pkgconfig ways to link libs
 
 //TOTEST FunctionUnit::compileInline
 TEST(Compilation, DISABLED_functionInline1){
 }
 
 TEST(Compilation, functionEntry1){
     std::unique_ptr<XreateManager> program(XreateManager::prepare(
         "func1 = function(a:: int):: int {a+8} \
          func2 = function::int; entry {12 + func1(4)}      \
         "));
 
     void* entryPtr = program->run();
     int (*entry)() = (int (*)())(intptr_t)entryPtr;
 
     int answer = entry();
     ASSERT_EQ(24, answer);
 }
 
 TEST(Compilation, full_IFStatementWithVariantType){
     XreateManager* man = XreateManager::prepare(
         "Color = type variant {RED, BLUE, GREEN}.\n"
         "\n"
         "   main = function(x::int):: bool; entry {\n"
         "       color = if (x == 0 )::Color {RED()} else {BLUE()}.\n"
         "       if (color == BLUE())::bool {true} else {false}\n"
         "   }"
     );
 
     bool (*main)(int) = (bool (*)(int)) man->run();
     ASSERT_FALSE(main(0));
     ASSERT_TRUE(main(1));
 }
 
+TEST(Compilation, full_Variant1){
+    XreateManager* man = XreateManager::prepare(R"Code(
+        OneArgument = type{x::int}.
+        TwoArguments = type{x::int, y::int}.
+
+        Command= type variant{
+            Add::TwoArguments,
+            Dec::OneArgument
+        }.
+
+        main = function::Command; entry {
+            Dec({x=2})::Command
+        }
+    )Code");
+
+    void (*main)() = (void (*)()) man->run();
+}
+
+TEST(Compilation, full_SwitchVariant1){
+    XreateManager* man = XreateManager::prepare(R"Code(
+        OneArgument = type{x::int}.
+        TwoArguments = type{x::int, y::int}.
+
+        Command= type variant{
+            Add::TwoArguments,
+            Dec::OneArgument
+        }.
+
+        main = function::int; entry {
+            //command = Dec({x = 8}):: Command.
+            command = Add({x= 3, y= 5}):: Command.
+
+            switch variant(command)::int
+            case(Add){command["x"] + command["y"]}
+            case(Dec){command["x"]}
+        }
+    )Code");
+
+    int (*mainFn)() = (int (*)()) man->run();
+    int result = mainFn();
+    ASSERT_EQ(8, result);
+}
+
 TEST(Compilation, full_StructUpdate){
     XreateManager* man = XreateManager::prepare(
     R"Code(
 
     Rec = type {
         a :: int,
         b:: int
     }.
 
     test= function:: int; entry {
         a = {a = 18, b = 20}:: Rec.
 
         b = a + {a = 11}:: Rec.
         b["a"]
     }
     )Code");
 
     int (*main)() = (int (*)()) man->run();
     int result = main();
 
     ASSERT_EQ(11, result);
 }
 
 TEST(Compilation, AnonymousStruct_init_index){
     std::string code =
 R"Code(
 
     main = function:: int; entry {
         x = {10, 15} :: {int, int}.
         x[1]
     }
 
 )Code";
 
     std::unique_ptr<XreateManager> man(XreateManager::prepare(move(code)));
     int (*main)() = (int (*)()) man->run();
 
     EXPECT_EQ(15, main());
 }
 
 TEST(Compilation, AnonymousStruct_init_update){
     std::string code =
 R"Code(
 
     main = function:: int; entry {
         x = {10, 15} :: {int, int}.
         y = x + {6}:: {int, int}.
         y[0]
     }
 
 )Code";
 
     std::unique_ptr<XreateManager> man(XreateManager::prepare(move(code)));
     int (*main)() = (int (*)()) man->run();
 
     EXPECT_EQ(6, main());
 }
 
diff --git a/cpp/tests/context.cpp b/cpp/tests/context.cpp
index b989947..942d862 100644
--- a/cpp/tests/context.cpp
+++ b/cpp/tests/context.cpp
@@ -1,497 +1,497 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/
- * 
+ *
  * frame-context.cpp
  *
  *  Created on: Dec 3, 2015
  *      Author: pgess <v.melnychenko@xreate.org>
  */
 
 #include "xreatemanager.h"
 #include "query/context.h"
 
 #include "gtest/gtest.h"
 #include <iostream>
 #include <boost/scoped_ptr.hpp>
 
 using namespace xreate;
 using namespace xreate::context;
 
 TEST(Context, frame_Context1){
 	details::tier1::XreateManager* man = details::tier1::XreateManager::prepare(
 		"	import raw (\"core/control-context.lp\").\n"
 		"	compute = function::int {\n"
 		"		0\n"
 		"	}\n"
 
 		"	computeFast = function:: int {\n"
 		"		context:: computation(fast).\n"
 
 		"		compute()\n"
 		"	}\n"
 
 		"	computePrecisely = function:: int {\n"
 		"		context:: computation(precise). \n"
 
 		"		compute()\n"
 		"	}\n"
 
                 "test = function(cmnd:: int):: int; entry {\n"
                 "   context:: arithmetic(iee754). \n"
 
                 "   if (cmnd > 0)::int {computePrecisely()} else {computeFast()} \n"
                 "}\n"
 	);
 
 	ContextQuery* query = (ContextQuery*) man->clasp->registerQuery(new ContextQuery(), QueryId::ContextQuery);
 	man->analyse();
 
 	CodeScope* scopeTestC = man->root->findFunction("compute")->getEntryScope();
 	const Domain& context = query->getContext(man->clasp->pack(scopeTestC));
 
 	int contextSize = context.size();
 	EXPECT_EQ(1, contextSize); //arithmetic(iee754)
 }
 
 TEST(Context, contextAsRequirementSuccessful1){
 	XreateManager* man = XreateManager::prepare(
 		"       import raw (\"core/control-context.lp\").\n"
 
                 "       case context::safe {\n"
 		"	funcSensitive = function::int {\n"
 		"		0\n"
 		"	}}\n"
 
 		"	test = function:: int; entry {\n"
 		"		context:: safe; test.\n"
 
 		"		funcSensitive()\n"
 		"	}\n"
 	);
 
 	int (*main)() = (int (*)()) man->run();
 	ASSERT_EQ(0, main());
 }
 
 TEST(Context, contextAsRequirementFailed){
 	XreateManager* man = XreateManager::prepare(
 		"       import raw (\"core/control-context.lp\").\n"
 
                 "       case context::safe {\n"
 		"	funcSensitive = function::int {\n"
 		"		0\n"
 		"	}}\n"
 
 		"	test = function:: int; entry {\n"
 		"		context:: non_safe; test.\n"
 
 		"		funcSensitive()\n"
 		"	}\n"
 	);
 
 	ASSERT_DEATH(man->run(), "findFunction");
 }
 
 TEST(Context, ContextPropagationNested){
 	XreateManager* man = XreateManager::prepare(
 		"       import raw (\"core/control-context.lp\").\n"
 
                 "       case context::safe {\n"
 		"	square = function(x:: int) ::int {\n"
 		"		x * x\n"
 		"	}}\n"
 
 		"	test = function:: int; entry {\n"
 		"		context:: safe; test.\n"
 
                 "               range = [1..10]:: [int].   \n"
                 "               loop fold(range->x::int, 0->acc):: int {   \n"
                 "                   acc + square(x)    \n"
                 "               }  \n"
                 "       }\n"
 	);
 
 	int (*main)() = (int (*)()) man->run();
 	ASSERT_EQ(385, main());
 }
 
 TEST(Context, ContextPropagationNestedInterfunction){
 
 	XreateManager* man = XreateManager::prepare(
         "	import raw (\"core/control-context.lp\").\n"
 	"	case context::toMillimeters {\n"
 	"		convertConcrete = function(source:: num)::num {\n"
 	"			10 * source \n"
 	"		}\n"
 	"	}\n"
 
 	"	case context::toInches {\n"
 	"		convertConcrete = function(source:: num)::num {\n"
 	"			2 * source \n"
 	"		}\n"
 	"	}\n"
 
         "convert= function(source:: num):: num { \n"
                 "convertConcrete(source) \n"
         "} \n"
 
 	"test = function(source:: num):: num; entry {\n"
 	"	context:: toMillimeters.\n"
 	"	convert(1)\n"
 	"}\n" );
 
 	int (*main)(int) = (int (*)(int)) man->run();
 	ASSERT_EQ(10, main(1));
 }
 
 TEST(Context, full_ContextBasedFunctionSpecialization){
 
 	XreateManager* man = XreateManager::prepare(
         "	import raw (\"core/control-context.lp\").\n"
 	"	case context::toMillimeters {\n"
 	"		convert = function(source:: num)::num {\n"
 	"					10 * source \n"
 	"		}\n"
 	"	}\n"
 
 	"	case context::toInches {\n"
 	"		convert = function(source:: num)::num {\n"
 	"			2 * source \n"
 	"		}\n"
 	"	}\n"
 
 	"test = function(vrnt:: int)::int; entry {\n"
 	"		switch(vrnt):: int\n"
 	"		case (0) {\n"
 	"			context:: toMillimeters.\n"
 	"			convert(1)\n"
 	"		}\n"
 	"\n"
 	"		case (1) {\n"
 	"			context:: toInches.\n"
 	"			convert(1)\n"
 	"		}\n"
 	"		case default {0}\n"
 	"	}" );
 
 	int (*main)(int) = (int (*)(int)) man->run();
 	ASSERT_EQ(10, main(0));
 	ASSERT_EQ(2, main(1));
 }
 
 TEST(Context, full_RuleContext){
 	/*
 	"rule context:: childs(Child)\n"
 	"	case artefact(Item)\n"
 	"	{\n"
 	"		artefact_depends(Item, Child)\n"
 	"	}";
 	*/
 
 	XreateManager* man = XreateManager::prepare(
                 "	import raw (\"core/control-context.lp\").\n"
 		"	case context:: toMilli {\n"
 		"		convert = function(length::int)::int{\n"
 		"			10 * length\n"
 		"		}\n"
 		"	}\n"
 		"\n"
 		"	case context:: toCenti {\n"
 		"		convert = function(length::int)::int{\n"
 		"			length\n"
 		"		}\n"
 		"	}\n"
 		"\n"
 		"	main=function::int; entry {\n"
 		"		context:: output(milli).\n"
 		"\n"
 		"		rule context::toMilli\n"
 		"		case (output(milli)) {truth}\n"
 		"\n"
 		"		convert(1)\n"
 		"	}" );
 
 	man->clasp->addRawScript("truth.");
 	int (*entry)() = (int (*)()) man->run();
 	ASSERT_EQ(10, entry());
 }
 
 TEST(Context, full_InheritedRuleContext){
     XreateManager* man = XreateManager::prepare(
 "	import raw (\"core/control-context.lp\"). \n"
 
 "	case context:: toMilli {\n"
 "		convert = function(length::int)::int{\n"
 "			10 * length\n"
 "		}\n"
 "	}\n"
 
 "	case context:: toCenti {\n"
 "		convert = function(length::int)::int{\n"
 "			length\n"
 "		}\n"
 "	}\n"
 "\n"
 
 "main = function(comm:: num)::num; entry{\n"
 "		rule context::X case (output(X)) {truth}\n"
 "\n"
 "		switch (comm)::num \n"
 "			case (0) {\n"
 "				context:: output(toMilli).\n"
 "				convert(1)\n"
 "			}\n"
 "			case default {\n"
 "				context:: output(toCenti).\n"
 "				convert(1)\n"
 "			}\n"
 "	}");
 
     man->clasp->addRawScript("truth.");
     int (*entry)(int) = (int (*)(int)) man->run();
     ASSERT_EQ(10, entry(0));
     ASSERT_EQ(1, entry(1));
 }
 
 
 
 TEST(Context, full_LateContext){
     details::tier1::XreateManager* man = details::tier1::XreateManager::prepare(
             "import raw (\"core/control-context.lp\").\n"
 
             "    convert = function(length:: num)::num{\n"
             "        0\n"
             "    }\n"
 
             "case context:: milli {\n"
             "    convert = function(length:: num)::num{\n"
             "        1000 * length\n"
             "    }\n"
             "}\n"
             "\n"
             "case context:: centi {\n"
             "    convert = function(length:: num)::num{\n"
             "        100 * length\n"
             "    }\n"
             "}\n"
             "\n"
             "calculate = function(length:: num)::num {\n"
             "    convert(length)\n"
             "}\n"
             "\n"
             "main = function(com:: num):: num; entry {\n"
                     "    switch (com):: num \n"
                     "    case (0) {\n"
                     "        context:: milli.\n"
                     "        calculate(1)\n"
                     "    }\n"
                     "\n"
                     "    case default{\n"
                     "        context:: centi. \n"
                     "        calculate(1)\n"
                     "    }\n"
             "}");
 
     man->analyse();
     ContextQuery* queryContext = reinterpret_cast<ContextQuery*>(man->clasp->getQuery(QueryId::ContextQuery));
-    Expression exprSwitch = man->root->findFunction("main")->__entry->getBody();
-    CodeScope* blockDefault = man->root->findFunction("main")->__entry->getBody().operands[1].blocks.front();
+    const Expression& exprSwitch = man->root->findFunction("main")->__entry->getBody();
+    const CodeScope* blockDefault = man->root->findFunction("main")->__entry->getBody().operands.at(1).blocks.front();
     ScopePacked blockDefaultId = man->clasp->pack(blockDefault);
     const Domain& domDefault = queryContext->getContext(blockDefaultId);
     ASSERT_EQ(1, domDefault.count(Expression(Atom<Identifier_t>("centi"))));
 
     std::list<ManagedFnPtr> variants = man->root->getFunctionSpecializations("convert");
     for (ManagedFnPtr f: variants){
             const Expression guard = f->guardContext;
             bool result = (guard.getValueString() == "centi" || guard.getValueString() == "milli" || !guard.isValid());
             ASSERT_TRUE(result);
     }
 
     const FunctionDemand& demMain = queryContext->getFunctionDemand("main");
     ASSERT_EQ(0, demMain.size());
 
     const FunctionDemand& demCalculate = queryContext->getFunctionDemand("calculate");
     ASSERT_EQ(1, demCalculate.size());
 
     int (*entry)(int) = (int (*)(int)) man->run();
     ASSERT_EQ(1000, entry(0));
     ASSERT_EQ(100, entry(1));
 }
 
 TEST(Context, loopContextExists){
     XreateManager* man = XreateManager::prepare (
         "import raw (\"core/control-context.lp\").\n"
 
         "interface(cfa){\n"
         "    operator fold:: annotation1.\n"
         "}\n"
         "\n"
         "main = function:: int; entry {\n"
         "    x = [1..10]:: [int].\n"
         "    sum = loop fold (x->el:: int, 0->sum):: int {\n"
         "        el + sum + f1()\n"
         "    }.  \n"
         "    sum\n"
         "}"
         "case context:: annotation1 {"
         " f1 = function::int {\n"
         "  	x = 0:: int.		 "
         "       x\n"
         " }"
         "}"
     );
 
     man->run();
 }
 
 TEST(Context, pathDependentContext){
     std::string program =
 R"CODE(
 import raw("core/control-context.lp").
 
 convert = function(length:: num) :: num {
     0
 }
 
 case context:: convert(milli, meters) {
     convert = function(length:: num) :: num {
         1000 * length
     }
 }
 
 case context:: convert(centi, meters) {
     convert = function(length:: num) :: num {
         100 * length
     }
 }
 
 case context:: convert(centi, kilo) {
     convert = function(length:: num) :: num {
         100000 * length
     }
 }
 
 case context:: convert(milli, kilo) {
     convert = function(length:: num) :: num {
         1000000 * length
     }
 }
 
 main = function(value::num, unitsInput::num, unitsOutput::num)::num; entry{
     switch (unitsInput)::num
     case (0) {
         test_fromMilli(value, unitsOutput)
     }
     case (1) {
         test_fromCenti(value, unitsOutput)
     }
 
     case default {0}
 }
 
 test_fromCenti = function(value::num, output::num)::num{
     context:: input(centi).
 
     switch(output):: num
     case (0)  {
         toMeters(value)
     }
 
     case (1) {
         toKilo(value)
     }
 
     case default {0}
 }
 
 test_fromMilli = function(value::num, output::num)::num{
     context:: input(milli).
 
     switch(output):: num
     case (0)  {
         toMeters(value)
     }
 
     case (1) {
         toKilo(value)
     }
 
     case default {0}
 }
 
 toMeters = function(value::num)::num {
         rule context:: convert(X, meters) case (input(X)) {truth}
 
         doConvert(value)
 }
 
 toKilo = function(value::num)::num {
         rule context:: convert(X, kilo) case (input(X)) {truth}
 
         doConvert(value)
 }
 
 doConvert = function(value::num)::num{
    convert(value)
 })CODE";
 
     boost::scoped_ptr<details::tier1::XreateManager> man(details::tier1::XreateManager::prepare(move(program)));
     man->clasp->addRawScript("truth.");
     man->analyse();
 
     int (*test)(int, int, int) = (int (*)(int, int, int))man->run();
 
     enum {INPUT_MILLI, INPUT_CENTI};
     enum {OUTPUT_METERS, OUTPUT_KILO};
 
     ASSERT_EQ(1000000, test(1, INPUT_MILLI, OUTPUT_KILO));
     ASSERT_EQ(200, test(2, INPUT_CENTI, OUTPUT_METERS));
 }
 
 //TODO recover context loop and enable the test
 TEST(Context, DISABLED_full_LoopContext){
     XreateManager* man = XreateManager::prepare(
     "	import raw (\"core/control-context.lp\")\n"
     "       case context:: a {\n"
     "	print = function:: string {\n"
     "		\"a\"\n"
     "	}}\n"
     "\n"
     "	case context:: b {\n"
     "	print = function:: string {\n"
     "		\"b\"\n"
     "	}}\n"
     "\n"
     "	case context:: c {\n"
     "	print = function:: string {\n"
     "		\"c\"\n"
     "	}}\n"
     "\n"
     "	case context:: d {\n"
     "	print = function:: string {\n"
     "		\"d\"\n"
     "	}}\n"
     "\n"
     "	start = function(command::int)::string; entry {\n"
     "		switch (command) :: string \n"
     "		case (0) {\n"
     "			context:: print(a); print(b); print(d).\n"
     "\n"
     "			loop context (\"print\") {\n"
     "				print()\n"
     "			}\n"
     "		}\n"
     "\n"
     "		case default {\n"
     "			context:: print(c).\n"
     "			loop context (\"print\") {\n"
     "				print()\n"
     "			}\n"
     "		}\n"
     "	}");
 
 
     char* (*main)(int)  =(char* (*)(int)) man->run();
     ASSERT_STREQ("c", main(1));
     ASSERT_STREQ("a", main(0));
 }
diff --git a/grammar/xreate.ATG b/grammar/xreate.ATG
index e9b8f81..82efffe 100644
--- a/grammar/xreate.ATG
+++ b/grammar/xreate.ATG
@@ -1,660 +1,660 @@
 //TODO add ListLiteral
 //TODO ExprTyped:  assign default(none) type
 
 #include "ast.h"
 #include "ExternLayer.h"
 #include "pass/adhocpass.h"
 #include <string>
 #include <stack>
 
 #define wprintf(format, ...) \
                 char __buffer[100];    \
                 wcstombs(__buffer, format, 100);   \
                 fprintf(stderr, __buffer, __VA_ARGS__)
                 
 using namespace std;
 
 COMPILER Xreate
 
  details::inconsistent::AST* root = nullptr;  // current program unit 
  
  void ensureInitalizedAST(){
    if (root == nullptr) root = new details::inconsistent::AST();
  }
  
  struct {
     std::stack<CodeScope*> scopesOld;
     CodeScope* scope = nullptr;
  } context;
  
  void pushContextScope(CodeScope* scope){
     context.scopesOld.push(context.scope);
     context.scope = scope;
  }
  
  void popContextScope(){
         context.scope = context.scopesOld.top();
         context.scopesOld.pop();
  }
      
 int nextToken()
 {
   scanner->ResetPeek();
   return scanner->Peek()->kind;
 }
 
 bool checkTokenAfterIdent(int key){
   if (la->kind != _ident) return false;
   return  nextToken()  == key;
 }
 
 bool checkParametersList()
 {
     return la->kind == _ident && nextToken() == _lparen;
 }
 
 bool checkInfix()
 {
   return la->kind == _ident && nextToken() == _ident;
 }
 
 bool checkIndex()
 {
   return la->kind == _ident && nextToken()  == _lbrack;
 }
 
 bool checkFuncDecl()
 {
   if (la->kind != _ident) return false;
   
   int token2 = nextToken();
   int token3 = scanner->Peek()->kind;
   
   return  token2  == _assign && (token3 == _function || token3 == _pre);
 }
 
 
 
 bool checkAssignment()
 {
   if (la->kind != _ident) return false;
   
   scanner->ResetPeek();
   int token2 = scanner->Peek()->kind;
   if (token2 == _lcurbrack) {
       scanner->Peek();
       int token3 = scanner->Peek()->kind;
       if (token3 != _rcurbrack) return false;
       
       int token4 = scanner->Peek()->kind;
       return token4 == _assign;
   }
   
   return  token2  == _assign;
 }
 
 void recognizeIdentifier(Expression& i){
     if (!context.scope->recognizeIdentifier(i)){       
         root->postponeIdentifier(context.scope, i);
     }
 }
 
 enum SwitchKind{SWITCH_NORMAL, SWITCH_META};
 
 CHARACTERS
   letter = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".
   any = ANY - '"'.
   digit = "0123456789".
   cr  = '\r'.
   lf  = '\n'.
   tab = '\t'.
 
 TOKENS
   ident = (letter | '_') {letter | digit | '_'}.
   number = (digit | '-' digit) {digit}.
   string = '"' { any } '"'.
   function = "function".
   pre =  "pre".  
   lparen = '('. 
   rparen = ')'.
   lbrack = '['.
   rbrack = ']'.
   lcurbrack = '{'.
   rcurbrack = '}'.
   equal = "==".
   assign = '='.
   implic = '-' '>'.
   colon = ':'.
   context = "context".
   tagcolon   = "::".
   lse = "<=".
   lss = "<".
   gte = ">=".
   gtr = ">".
   
   ne1 = "!=".
   ne2= "<>".
   
 
 COMMENTS FROM "/*" TO "*/" NESTED
 COMMENTS FROM "//" TO lf
 
 IGNORE cr + lf + tab
 
 PRODUCTIONS
 
 Xreate =    (. Function* function; ensureInitalizedAST(); .)
 {(  RuleDecl 
     | InterfaceData | Imprt | ContextSection | GuardSection
     | IF(checkFuncDecl()) FDecl<function>  (. root->add(function); .)
     | TDecl 
     | SkipModulesSection
 )}                                         (.  .)
 .
 
 Ident<std::wstring& name>
 = ident                                     (. name = t->val; .).
 
 VarIdent<Expression& e>
 = ident                                     (. e = Expression(Atom<Identifier_t>(t->val)); .)
   [ lcurbrack (                              
         ident                               (. SemErr(coco_string_create("var version as ident is not implemented yet")); .)
       | number                              (. Attachments::put<versions::VariableVersion>(e, Atom<Number_t>(t->val).get()); .)
   ) rcurbrack ]
 .
   
 
 FDecl<Function*& f> =       (. std::wstring fname; std::wstring argName; TypeAnnotation typIn; TypeAnnotation typOut; bool flagIsPrefunct = false; Expression binding; .)
 Ident<fname> assign 
 [pre            (. flagIsPrefunct = true; .)]
 function 		(. f = new Function(fname); f->isPrefunction = flagIsPrefunct; CodeScope* entry = f->getEntryScope(); .)
 
 ['(' Ident<argName> tagcolon ExprAnnotations<binding>  (. f->addBinding(Atom<Identifier_t>(argName), move(binding)); .)
 {',' Ident<argName> tagcolon ExprAnnotations<binding>  (. f->addBinding(Atom <Identifier_t>(argName), move(binding));.)
 } ')']
 
 [ tagcolon  
 ( IF(flagIsPrefunct) FnTag<f>
   |  Type<typOut>
 )
 {';' FnTag<f> }]
-BDecl<entry>    (. entry->getBody().bindType(move(typOut));.)
+BDecl<entry>    (. const_cast<Expression&>(entry->getBody()).bindType(move(typOut));.)
 .
 
 ContextSection<>=                       (. Expression context; Function* f; .)
     "case" "context" tagcolon MetaSimpExpr<context>  
     lcurbrack { FDecl<f>                    (. f->guardContext = context; root->add(f); .)
     } rcurbrack.
     
 GuardSection<>=                       (. Expression guard; Function* f; .)
     "guard" tagcolon MetaSimpExpr<guard>  
     lcurbrack { FDecl<f>                    (. f->guard = guard; root->add(f); .)
     } rcurbrack.    
 
   /**
    *                          TYPES  
    * 
    */
 TypeTerm<TypePrimitive& typ> =                       (. std::wstring tid; .)
   ("string" (. typ = TypePrimitive::String;.)
   | "num"   (. typ = TypePrimitive::Num;.)
   | "int"   (. typ = TypePrimitive::Int;.)
   | "float" (. typ = TypePrimitive::Float;.)
   | "bool" (. typ = TypePrimitive::Bool; .)
   | "i8"    (. typ = TypePrimitive::I8; .)
   | "i32"   (. typ = TypePrimitive::I32; .)
   | "i64"   (. typ = TypePrimitive::I64; .)
   ).
 
 Type<TypeAnnotation& typ> =  (. TypeAnnotation typ2; TypePrimitive typ3; std::wstring tid, field; .)
 ( 
   TList<typ>   
 | TStruct<typ>
 | TVariant<typ>
 | TypeTerm<typ3> (. typ = typ3; .) 
 | IF (checkIndex()) Ident<tid> lbrack
       Ident<field>      (. typ = TypeAnnotation(TypeOperator::ACCESS, {}); typ.__valueCustom = Atom<Identifier_t>(tid).get(); typ.fields.push_back(Atom<Identifier_t>(field).get()); .)
       {',' Ident<field> (.  typ.fields.push_back(Atom<Identifier_t>(field).get());  .)
       } rbrack
       
 | Ident<tid>            (. typ = TypeAnnotation(TypeOperator::CUSTOM, {}); typ.__valueCustom = Atom<Identifier_t>(tid).get(); .)
     ['(' Type<typ2>     (. typ.__operator = TypeOperator::CALL; typ.__operands.push_back(typ2); .)
     {',' Type<typ2>     (. typ.__operands.push_back(typ2); .)
     } ')']
 ) .
 
 TList<TypeAnnotation& typ> =            (.      TypeAnnotation ty; .)
     '[' Type<ty> ']'                    (. typ = TypeAnnotation(TypeOperator::ARRAY, {ty}); .)
 .
 
 TStruct<TypeAnnotation& typ> = (. TypeAnnotation t; std::wstring key; size_t keyCounter=0; .)
   lcurbrack
     (
         IF(checkTokenAfterIdent(_tagcolon)) Ident<key> tagcolon Type<t> 
         | Type<t>       (. key = to_wstring(keyCounter++); .)
         
     )     (. typ = TypeAnnotation(TypeOperator::STRUCT, {t}); typ.fields.push_back(Atom<Identifier_t>(key).get()); .)
     {',' (
         IF(checkTokenAfterIdent(_tagcolon)) Ident<key> tagcolon Type<t> 
         | Type<t>       (. key = to_wstring(keyCounter++); .)
         
         ) (. typ.__operands.push_back(t); typ.fields.push_back(Atom<Identifier_t>(key).get()); .)
     } rcurbrack.
   
 TVariant<TypeAnnotation& typ>=  (. TypeAnnotation t, typVoid(TypeOperator::STRUCT, {}); std::vector<TypeAnnotation> operands; std::vector<Atom<Identifier_t>> keys; std::wstring variant; .)
     "variant" lcurbrack
     Ident<variant>              (. t=typVoid; .)        
     [tagcolon Type<t>]          (. keys.push_back(Atom<Identifier_t>(variant)); operands.push_back(t); .)
                           
     {',' Ident<variant>         (. t=typVoid; .)        
     [tagcolon Type<t>]          (. keys.push_back(Atom<Identifier_t>(variant)); operands.push_back(t); .)
     }                           
     rcurbrack                   (. typ = TypeAnnotation(TypeOperator::VARIANT, {}); typ.__operands = operands;  typ.addFields(std::move(keys)); .)
 .    
 
  TDecl =  (. TypeAnnotation t; std::wstring tname, arg; std::vector<Atom<Identifier_t>> args; .)
   Ident<tname> assign "type"
   ['('  Ident<arg>        (. args.push_back(Atom<Identifier_t>(arg));   .)
   {',' Ident<arg>         (. args.push_back(Atom<Identifier_t>(arg));   .)
   } ')']
   Type<t>'.'              (. t.addBindings(move(args)); root->add(move(t), Atom<Identifier_t>(tname)); .)
   .
   
 ContextDecl<CodeScope * scope> =        (. Expression tag; .)
 context tagcolon 
 MetaSimpExpr<tag>                     (. scope->tags.push_back(tag); .)
 {';' MetaSimpExpr<tag>                (. scope->tags.push_back(tag); .)
 }.
 
 VDecl<CodeScope* f> =                       (. std::wstring vname; Expression var, value;.)
     VarIdent<var> assign ExprTyped<value>   (. Symbol identSymbol = f->addDefinition(move(var), move(value)); 
                                                 Attachments::put<SymbolAlias>(value, identSymbol);
                                             .)
 .
 
 BDecl<CodeScope* scope> =  lcurbrack      (. Expression body; pushContextScope(scope);  .)
     {(IF(checkAssignment()) VDecl<scope> '.'
     | RuleContextDecl<scope>  
     | ContextDecl<scope>'.'
     | ExprTyped<body>                     (. scope->setBody(body); Attachments::put<SymbolAlias>(body, Symbol{ScopedSymbol::RetSymbol, scope});.)
     )}
     rcurbrack                             (. popContextScope(); .) 
 . 
 
 IfDecl<Expression& e> =     (. Expression cond; ManagedScpPtr blockTrue = root->add(new CodeScope(context.scope)); ManagedScpPtr blockFalse = root->add(new CodeScope(context.scope)); .)
 "if" '(' Expr<cond> ')'                         (. e = Expression(Operator::IF, {cond}); .)
 tagcolon ExprAnnotations<e> 
 BDecl<&*blockTrue> "else" BDecl<&*blockFalse>   (.  e.addBlock(blockTrue); e.addBlock(blockFalse); .)
 .
 
 LoopDecl<Expression& e> = 
   (. Expression eIn, eAcc, eFilters; std::wstring varEl, varAcc, contextClass; Expression tagsEl;
     ManagedScpPtr block = root->add(new CodeScope(context.scope)); .)
    "loop"
    ("map" '(' Expr<eIn> implic Ident<varEl>     (. e = Expression(Operator::MAP, {eIn}); .)
     tagcolon ExprAnnotations<tagsEl> ')' tagcolon ExprAnnotations<e> 
         (.
             e.addBindings({Atom<Identifier_t>(varEl)});
             block->addBinding(Atom<Identifier_t>(varEl), move(tagsEl)); 
         .)
     BDecl<&*block>
         (. e.addBlock(block);  .)
 
   |"fold" 
     ("inf" '(' Expr<eAcc> implic Ident<varAcc> ')' 
         (.
                 e = Expression(Operator::FOLD_INF, {eAcc});
                 e.addBindings({Atom<Identifier_t>(varAcc)});
                 block->addBinding(Atom<Identifier_t>(varAcc), Expression());
         .)        
      tagcolon ExprAnnotations<e> BDecl<&*block>
         (.  e.addBlock(block); .)
   
      | '(' Expr<eIn> implic Ident<varEl> tagcolon ExprAnnotations<tagsEl> ['|' Expr<eFilters> ] ',' Expr<eAcc> implic Ident<varAcc>')'
             (.
                 e = Expression(Operator::FOLD, {eIn, eAcc});
                 e.addBindings({Atom<Identifier_t>(varEl), Atom<Identifier_t>(varAcc)});
             .)
         tagcolon ExprAnnotations<e> 
             (.  
                 block->addBinding(Atom<Identifier_t>(varEl), move(tagsEl));
                 block->addBinding(Atom<Identifier_t>(varAcc), Expression());
             .)
         BDecl<&*block>
             (.  e.addBlock(block);             .)
     )
   | "context" '(' string                          (. contextClass = t->val; .)
     ')' BDecl<&*block> 
         (. e = Expression(Operator::LOOP_CONTEXT, {Expression(Atom<String_t>(std::move(contextClass)))});
             e.addBlock(block);
          .)
 ).
    
 //              Switches   
 SwitchDecl<Expression& eSwitch, SwitchKind flagSwitchKind> = (. TypeAnnotation typ; eSwitch = Expression(Operator::SWITCH, {}); Expression eCondition; Expression tag;.)
 "switch" 
     (
         SwitchVariantDecl<eSwitch>
         | lparen ExprTyped<eCondition> rparen tagcolon  ExprAnnotations<eSwitch>  (. eSwitch.operands.push_back(eCondition);.)
           CaseDecl<eSwitch, flagSwitchKind> {CaseDecl<eSwitch, flagSwitchKind>}
     ) 
 .
   
 CaseDecl<Expression& outer, SwitchKind flagSwitchKind> = (. ManagedScpPtr scope = root->add(new CodeScope(context.scope)); Expression condition; .)
   "case" 
   ( IF(flagSwitchKind == SWITCH_META)
         lparen MetaSimpExpr<condition> rparen BDecl<&*scope>  (. Expression exprCase(Operator::CASE, {}); exprCase.addTags({condition}); exprCase.addBlock(scope); outer.addArg(move(exprCase));.)
         
     | "default" BDecl<&*scope>                    (. Expression exprCase(Operator::CASE_DEFAULT, {});       
                                                    exprCase.addBlock(scope); 
                                                    outer.operands.insert(++outer.operands.begin(), exprCase); .)
   
     | lparen CaseParams<&*scope> rparen         (. ManagedScpPtr scopeBody = root->add(new CodeScope(&*scope)); Expression exprCase(Operator::CASE, {}); .)
       BDecl<&*scopeBody>                                (. exprCase.addBlock(scope); exprCase.addBlock(scopeBody); outer.addArg(move(exprCase)); .)
  ).
 
 CaseParams<CodeScope* scope> =           (. Expression condition; Expression guard(Operator::LOGIC_AND, {}); pushContextScope(scope); .)
  ExprTyped<condition>                  (. guard.addArg(Expression(condition)); .)
    {',' ExprTyped<condition>             (. guard.addArg(Expression(condition)); .)
    }                                     (. scope->setBody(guard); popContextScope(); .)
 .
 
 SwitchVariantDecl<Expression& expr> =                                        
             (. Expression varTested; std::wstring varAlias; bool flagAliasFound = false; expr = Expression(Operator::SWITCH_VARIANT, {}); .)
                 
     "variant" lparen Expr<varTested> [implic Ident<varAlias>
             (. flagAliasFound = true; .) 
             
     ] [tagcolon ExprAnnotations<varTested>] rparen tagcolon ExprAnnotations<expr>  
             (. expr.addArg(std::move(varTested)); 
                 if (flagAliasFound) {
                     expr.addBindings({Atom<Identifier_t>(varAlias)}); 
                     
                 } else {
                     if(varTested.__state != Expression::IDENT){
                         SemErr(coco_string_create("Switch variant expects identifier"));
                         
                     }
                     
                     expr.addBindings({Atom<Identifier_t>(string(varTested.getValueString()))});
                 }
             .)
                 
     CaseVariantDecl<expr> {CaseVariantDecl<expr>}
 .    
 
 CaseVariantDecl<Expression& expr> =   (. ManagedScpPtr scope = root->add(new CodeScope(context.scope)); std::wstring key; scope->addBinding(Atom<Identifier_t>(string(expr.bindings.front())), Expression()); .)
     "case" lparen Ident<key> rparen   (. expr.addArg(root->recognizeVariantConstructor(Atom<Identifier_t>(std::move(key))));  .)
     BDecl<&*scope>                    (. expr.addBlock(scope); .)
 .    
     
 IntrinsicDecl<Expression& outer>=        (. std::wstring name; .)
 "intrinsic" Ident< name>                 (. outer = Expression(Operator::CALL_INTRINSIC, {}); outer.setValue(Atom<Identifier_t>(name)); .)
 lparen [CalleeParams<outer>] rparen .
   
                               /*============================ INTERFACES ===============================*/
 Imprt<> =                           
 "import" "raw" lparen string      (. root->__rawImports.push_back(Atom<String_t>(t->val).get()); .) 
 rparen '.'.
 
 InterfaceData<> = "interface" '('
   (   "dfa" ')'  InterfaceDFA
     | "extern-c" ')' InterfaceExternC
     | "cfa" ')' InterfaceCFA
     | "adhoc" ')' InterfaceAdhoc
     
   ).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
 
 InterfaceAdhoc<> = 
     '{' { PrefunctionSchemeDecl }  '}'.
      
 PrefunctionSchemeDecl<> =         (. TypeAnnotation typReturn; std::wstring prefName; Expression exprCases; .)
     pre function Ident<prefName> tagcolon Type<typReturn>
     lcurbrack SwitchDecl<exprCases, SWITCH_META> rcurbrack
                                   (. Expression prefData(Operator::CALL, {Atom<Identifier_t>(prefName), exprCases}); 
                                      prefData.bindType(typReturn); 
                                      root->addInterfaceData(Adhoc, move(prefData));  
                                   .).    
 
 
 InterfaceExternC<>  =   (. ExternData data; .)
   '{' {IncludeExternDecl<data> | LibExternDecl<data> } '}'
       (. root->addExternData(move(data));  .)
 .
 
 LibExternDecl<ExternData& data> =       (. std::wstring pkgname, libname; .)
   Ident<libname> assign "library" tagcolon "pkgconfig" 
   '(' string            (. pkgname = t->val; .)
   ')' '.'               (. data.addLibrary(Atom<Identifier_t>(libname), Atom<String_t>(pkgname)); .)
 . 
 
 IncludeExternDecl<ExternData& data> =   (. Expression inc; .)
   "include" StructLiteral<inc> '.'              (. data.addIncludeDecl(move(inc)); .)
 .
   
 InterfaceDFA<> = '{' { InstructDecl } '}' .
 
 InstructDecl =                        (.Operator op; Expression tag; 
                                   Expression scheme; 
                                   std::vector<Expression>& tags = scheme.operands; 
                                   tags.push_back(Expression()); /* return value */ .)
 "operator" InstructAlias<op> tagcolon '('      (.scheme.setOp(op); .)
 [
   MetaSimpExpr<tag>             (. tags.push_back(tag); .)
   {
       ',' MetaSimpExpr<tag>     (. tags.push_back(tag); .)
   }
 ] ')' [ implic MetaSimpExpr<tag>             (. tags[0] = tag; .) 
       ]                                      (. root->addDFAData(move(scheme)); .)
 '.'.
 
 InstructAlias<Operator& op> = 
 (
    "map"  (. op = Operator::MAP; .)
   | "list_range" (. op = Operator::LIST_RANGE; .)
   | "list"       (. op = Operator::LIST; .)
   | "fold"       (. op = Operator::FOLD; .)
   | "index"      (. op = Operator::INDEX; .) 
 ). 
 
 
 InterfaceCFA<> = '{' { InstructCFADecl } '}' .
 
 InstructCFADecl<> =                          (.Operator op; Expression tag; 
                                                 Expression scheme; 
                                                 std::vector<Expression>& tags = scheme.operands;  .)
 
 "operator" InstructAlias<op> tagcolon     (. scheme.setOp(op); .)
 [
   MetaSimpExpr<tag>             (. tags.push_back(tag); .)
   {
       ',' MetaSimpExpr<tag>     (. tags.push_back(tag); .)
   }
 ] '.'                           (. root->addInterfaceData(CFA, move(scheme)); .).
     
                               /*============================ METAPROGRAMMING ===============================*/
 // TagsDecl<CodeScope* f> = (. Expression tag; TagModifier mod = TagModifier::NONE; .)
 // ':' { MetaSimpExpr<tag> (. /*f.addTag(std::move(tag), mod); */ .)
 // }.
 
 
 FnTag<Function* f> = (. Expression tag; TagModifier mod = TagModifier::NONE; .)
 MetaSimpExpr<tag>
 ['-' TagMod<mod>] (. f->addTag(std::move(tag), mod); .).
 
 TagMod<TagModifier& mod> = 
 (  "assert" (. mod = TagModifier::ASSERT; .)
  | "require" (. mod = TagModifier::REQUIRE; .)
 ).
  
 RuleDecl<> =
 "rule" tagcolon         		(. RuleArguments args; RuleGuards guards; DomainAnnotation typ; std::wstring arg; .)
 '(' Ident<arg> tagcolon Domain<typ>  	(. args.add(arg, typ); .)
 {',' Ident<arg> tagcolon Domain<typ>  	(. args.add(arg, typ); .)
 } ')'
 ["case" RGuard<guards> {',' RGuard<guards>}]
 '{' RBody<args, guards> '}' .    	
 
 /* - TODO use RGuard for guards-*/
 RuleContextDecl<CodeScope* scope> =     (.Expression eHead, eGuards, eBody; .)
 "rule" "context" tagcolon MetaSimpExpr<eHead>
 "case" lparen MetaSimpExpr<eGuards> rparen
 '{' MetaSimpExpr<eBody> '}'             (.scope->contextRules.push_back(Expression(Operator::CONTEXT_RULE, {eHead, eGuards, eBody})); .).
 
 Domain<DomainAnnotation& dom> = 
 (
   "function"  				(. dom = DomainAnnotation::FUNCTION; .)
   | "variable"    			(. dom = DomainAnnotation::VARIABLE; .)
 ).
 
 RGuard<RuleGuards& guards>=          (. Expression e; .)
 MetaExpr<e>                       (. guards.add(std::move(e)); .).
 
 MetaExpr<Expression& e>=            (.Operator op; Expression e2; .)
 MetaExpr2<e>
 [MetaOp<op> MetaExpr2<e2>           (. e = Expression(op, {e, e2}); .)
 ].
 
 MetaExpr2<Expression& e>=
 (
 '(' MetaExpr<e> ')'
 | MetaSimpExpr<e>
 ).
 
 MetaSimpExpr<Expression& e>=      (. std::wstring i1, infix; Expression e2; .)
 ( '-' MetaSimpExpr<e2>            (. e = Expression(Operator::NEG, {e2}); .)
 | IF(checkParametersList()) Ident<i1>   (. e = Expression(Operator::CALL, {Expression(Atom<Identifier_t>(i1))}); .)
 '(' [ MetaCalleeParams<e> ] ')'
 | IF(checkInfix()) Ident<i1> Ident<infix> MetaSimpExpr<e2>                                       
                                         (. e = Expression(Operator::CALL, {Expression(Atom<Identifier_t>(infix))});
                                            e.addArg(Expression(Atom<Identifier_t>(i1)));
                                            e.addArg(std::move(e2));
                                         .)
 | Ident<i1>                             (. e = Expression(Operator::CALL, {Atom<Identifier_t>(i1)}); .)
 ).
 
 MetaCalleeParams<Expression& e> = (. Expression e2; .)
   MetaSimpExpr<e2>	     	(. e.addArg(Expression(e2)); .)
   {',' MetaSimpExpr<e2>		(. e.addArg(Expression(e2)); .)
   }.
 
 RBody<const RuleArguments& args, const RuleGuards& guards> =
                                   (. Expression e; std::wstring msg; .)
  "warning" MetaExpr<e> ["message" string (. msg = t->val; .)
 ]                                 (. root->add(new RuleWarning(RuleArguments(args), RuleGuards(guards), std::move(e), Atom<String_t>(msg))); .)
  .
 
 MetaOp< Operator& op> =
  implic                          (. op = Operator::IMPL; .)
 .
 
         /*============================ Expressions ===============================*/
 ExprAnnotations<Expression& e> = (. TypeAnnotation typ; std::list<Expression> tags; Expression tag; e.tags.clear();.)
 Type<typ>                    (. e.bindType(move(typ)); .)
   {';' MetaSimpExpr<tag>     (. tags.push_back(tag); .)
   }                          (. e.addTags(tags); .)
 .
   
 ExprTyped<Expression&e> = Expr<e> [tagcolon ExprAnnotations<e>].
 
 Expr< Expression& e>         (. Operator op; Expression e2; .)
 = ExprArithmAdd<e>		 
   [ RelOp<op>
     ExprArithmAdd<e2>      (. e = Expression(op, {e, e2});  .)
   ].
 
 ExprArithmAdd< Expression& e>=      (. Operator op; Expression e2; .)
   ExprArithmMul< e>
   [ AddOp< op>
     ExprArithmAdd< e2>         (. e = Expression(op, {e, e2});.)
   ].
 
 ExprArithmMul< Expression& e>         (. Operator op; Expression e2; .)
 = ExprPostfix< e>
   [ MulOp< op>
     ExprArithmMul< e2>        (. e = Expression(op, {e, e2}); .)
   ].
 
 ExprPostfix<Expression& e> 
 = Term<e> 
   [                                  (. e = Expression(Operator::INDEX, {e}); .)
     {lbrack CalleeParams<e> rbrack }
   ].
 
 
 Term< Expression& e>       (. std::wstring name; e = Expression(); .)
 =                        
   (IF (checkParametersList()) Ident< name> 
                                     (. e = Expression(Operator::CALL, {Atom<Identifier_t>(name)}); root->recognizeVariantConstructor(e); .)
   '(' [CalleeParams<e>] ')'
   | VarIdent<e>                     (. recognizeIdentifier(e); .)
   | ListLiteral<e>                  (. /* tuple */.)    
   | StructLiteral<e>                (. /* struct */.)
   | LoopDecl<e>
   | IfDecl<e>   
   | SwitchDecl<e, SWITCH_NORMAL>
   | AdhocDecl<e>
   | IntrinsicDecl<e>
   | number                          (. e = Expression(Atom<Number_t>(t->val)); .)
   | string                          (. e = Expression(Atom<String_t>(t->val)); .)
   | "true"                          (. e = Expression(Atom<Number_t>(1)); e.bindType(TypePrimitive::Bool); .)
   | "false"                         (. e = Expression(Atom<Number_t>(0)); e.bindType(TypePrimitive::Bool); .)
   | '-' Term<e>                     (. e = Expression(Operator::NEG, {e}); .)
   | '(' ExprTyped<e> ')'  
   ).
   
 StructLiteral<Expression& e> =                     (. std::wstring key; Expression val; std::list<Atom<Identifier_t>> keys; size_t keyCounter=0; .)
   lcurbrack 
         (IF(checkTokenAfterIdent(_assign)) Ident<key> '=' Expr<val>
         | Expr<val>                                (. key = to_wstring(keyCounter++); .)
         )                                          (. keys.push_back(Atom<Identifier_t>(key)); e = Expression(Operator::LIST_NAMED, {val}); .)
   {',' (IF(checkTokenAfterIdent(_assign)) Ident<key> '=' Expr<val>
         | Expr<val>                                (. key = to_wstring(keyCounter++); .)
        )                                           (. e.addArg(Expression(val)); keys.push_back(Atom<Identifier_t>(key)); .)
   } rcurbrack                                      (. e.addBindings(keys.begin(), keys.end()); .)
   .
   
 ListLiteral<Expression& e> =  (. Expression eFrom, eTo; .)
 '['                                                             
 [ Expr<eFrom>                                                   (. e.addArg(Expression(eFrom)); .)
 (".."  Expr<eTo>                                                (. e.addArg(Expression(eTo)); e.setOp(Operator::LIST_RANGE); .)
  |{',' Expr<eFrom>                                              (. e.addArg(Expression(eFrom)); .)
 }                                                               (. e.setOp(Operator::LIST); .) 
 ) ] ']'.
 
 AdhocDecl<Expression& e> = (. Expression command; .)
 "ad" "hoc" MetaSimpExpr<command>       (. adhoc::AdhocExpression exprAdhoc; exprAdhoc.setCommand(command); e = exprAdhoc; .).
 
 CalleeParams<Expression& e> = (. Expression e2; .)
   ExprTyped<e2>		(. e.addArg(Expression(e2)); .)
   {',' ExprTyped<e2> 		(. e.addArg(Expression(e2)); .)
   }.
 
 AddOp< Operator& op>
 =                        (. op = Operator::ADD; .)
   ( '+'
   | '-'                  (. op = Operator::SUB; .)
   ).
 
 MulOp< Operator& op>
 =                        (. op = Operator::MUL; .)
   ( '*'
   | '/'                  (. op = Operator::DIV; .)
   ).
 
 RelOp< Operator& op>
 =                         (. op = Operator::EQU; .)
   ( equal
   | (ne1 | ne2)           (. op = Operator::NE; .)
   
   | lse                   (. op = Operator::LSE; .)
   | lss                   (. op = Operator::LSS; .)
   
   | gte                   (. op = Operator::GTE; .)
   | gtr                   (. op = Operator::GTR; .)
   
   ).
   
 SkipModulesSection = "module" '{' {ANY} '}'.  
   
 END Xreate.