% 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/.

%%  INPUT:
%%    - latex_scope_demand(Scope, Subject)
%%        Initial demand from clients
%%
%%    - latex_registered_subjects(Subject, PossibleDecision)
%%        Clients register possible decisions for respective subjects
%%
%%    - latex_fn_signature
%%
%%  OUTPUT:
%%    - latex_fn_demand(Fn, Subject)
%%        Which functions demand hidden latex arguments
%%
%%    - latex_decision(Scope, Subject, Decision)
%%        Provided decisions, values for hidden latex arguments
%%
%%  SIGNATURES:
%%    -Subject: string
%%

%  CONTEXT PROPAGATION
%===========================================================

%  nested scope propagation:
bind_scope(Scope, Context, Info):- 
  bind_scope(ScopeParent, Context, Info);
  cfa_parent(Scope, scope(ScopeParent)).
  
%  Strong or Uniform inter-function propagation:
bind_scope(Scope, Context, Info):- 
  bind_scope(ScopeParent, Context, Info): cfa_call(ScopeParent, FnCurrent); 
  cfa_parent(Scope, function(FnCurrent)); cfa_call(_, FnCurrent);   
  bind_scope(_, Context, Info); scope(Scope).  
  
%  weak inter-function propagation
bind_scope(Scope, Context, weak(ScopeParent)):- 
  not bind_scope(Scope, Context, strong);
  bind_scope(ScopeParent, Context, strong);
  cfa_call(ScopeParent, FnCurrent);
  cfa_parent(Scope, function(FnCurrent)).  


%   DEMAND
%===========================================================

%demand propagations: scope level  
latex_scope_demand(Scope, Subject):-         
  latex_scope_demand(ScopeChild, Subject);
  cfa_parent(ScopeChild, scope(Scope)).
  
%propagation: fn level
latex_fn_demand(Fn, Subject):-
  latex_scope_demand(ScopeFnBody, Subject);
  cfa_parent(ScopeFnBody, function(Fn)).  
  
latex_fn_demand_ordered(Fn, Subject, Id):- 
  Id= #sum{ 1, SubjLess : latex_fn_demand(Fn, SubjLess), SubjLess < Subject};
  latex_fn_demand(Fn, Subject).  
  
%propagation: inter-fn level
latex_scope_demand(Scope, Subject):-     
  latex_fn_demand(FnCallee, Subject);
  not latex_decision(Scope, Subject, _);
  cfa_call(Scope, FnCallee).

%   DECISIONS    
%===========================================================

latex_decision(Scope, Subject, Decision):-     
  latex_fn_demand(FnCallee, Subject);
  bind_scope(Scope, Decision, strong);
  cfa_call(Scope, FnCallee);
  latex_registered_subjects(Subject, Decision).

%late decision
late((ScopeCaller, Subject), SubjectS, (AnyDecision), latex_decision(ScopeCaller, Subject, AnyDecision)):-     
  scope_fn(ScopeCaller, FnCaller);
  cfa_parent(FnCallerBody, function(FnCaller));
  latex_symbol(FnCaller, Subject, SubjectS);
  
  cfa_call(ScopeCaller, FnCallee);
  latex_fn_demand(FnCallee, Subject);
  latex_registered_subjects(Subject, AnyDecision).
  
  
% UTILITY
%===========================================================
latex_symbol(Fn, Topic, s(TopicsOffset + TopicId, -2, FnBody)):-
  cfa_parent(FnBody, function(Fn));
  latex_parameters_group_offset(TopicsOffset);
  latex_fn_demand_ordered(Fn, Topic, TopicId).  
  
  
%   IMPLEMENTATION    
%===========================================================  

scope_fn(Scope, Fn):-cfa_parent(Scope, function(Fn)).
scope_fn(Scope, Fn):- 
  scope_fn(ScopeParent, Fn);
  cfa_parent(Scope, scope(ScopeParent)).

latex_parameters_group_offset(1000).