% 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/.

%defines
  impl(solid; llvm_const_array; on_the_fly). 
  op(seqaccess). op(randaccess).
  
  relation(recommends; satisfied; unsupported).
  relation_score(satisfied, 0).
  relation_score(recommends, 1).
  relation_score(unsupported, -1).
  score(-1..1).

  %domain facts:
relation_op(seqaccess, on_the_fly, recommends).
relation_op(randaccess, llvm_const_array, recommends).
relation_op(randaccess, on_the_fly, unsupported).
        
  %AST ATTACHMENTS
attach_operator_map(none, op(seqaccess)).
attach_operator_fold(none, op(seqaccess), none).

attach_operator_list_range(impl(on_the_fly)).
attach_operator_list(impl(solid)).
attach_operator_index(op(randaccess)).

  %CLUSTERS
cluster_link(VTo, VFrom):-                %aliases
  dfa_connection(VTo, VFrom, strong).
  
cluster_link(VResult, VSource):-          %Operator MAP
  ast_op_map(VResult, VSource, _).
  
cluster_root(V):- 
  not cluster_link(V, _);
  v(V).

var_cluster(V, V):-                       %self referencing
  cluster_root(V).
  
var_cluster(VRoot, VTo):-                 %propagation down the tree
  cluster_link(VTo, VFrom);
  var_cluster(VRoot, VFrom).
  
  
  %ALGORITHM  
-impl_fulfill(OP, IMPL):- 
  relation_op(OP, IMPL, unsupported).
  
impl_fulfill(OP, IMPL, SCORE):- 
  SCORE = #sum{SCORE1, (OP, IMPL, RL): relation_op(OP, IMPL, RL), relation_score(RL, SCORE1)};
  not -impl_fulfill(OP, IMPL);
  op(OP); impl(IMPL).
    
-impl_fulfill_cluster(Var0, Impl):- 
  var_cluster(Var0, Var_Any); 
  bind(Var_Any, op(Op)); 
  -impl_fulfill(Op, Impl).
  
impl_fulfill_cluster(VAR0, IMPL, Score):- 
    Score = #sum{SCORE, (OP, IMPL, VAR_ANY): impl_fulfill(OP, IMPL, SCORE), var_cluster(VAR0, VAR_ANY), bind(VAR_ANY, op(OP))};
  bind(VAR0, impl(IMPL)); 
  cluster_root(VAR0); 
  not -impl_fulfill_cluster(VAR0, IMPL).
  
  
  %OUTPUT
containers_impl(V, Impl):-
  containers_impl(VRoot, Impl);
  var_cluster(VRoot, V).

containers_impl(V, solid(Size)):-
  impl_fulfill_cluster(V, solid, _);
  ast_op_list(V, Size);
  cluster_root(V).
  
containers_impl(V, on_the_fly):-
  impl_fulfill_cluster(V, on_the_fly, _);
  ast_op_list_range(V);
  cluster_root(V).  
  
%optimization
%  #maximize {SCORE, (VAR0, IMPL) : impl_fulfill_cluster(VAR0, IMPL, SCORE)}.

#show var_cluster/2.
#show impl_fulfill_cluster/3.