%INPUT:
% kleo_registered_subjects(Scope, Option, Subject) 

%bind_scope_decision - scope has decision for demand of one of its subscopes.

%   CLIENTS
%===========================================================
% clients defined downstream 

%Register fn argument demand
kleo_registered_subjects(ScopeCaller, kleo_arg(Subject), Guard):-
  kleo_fn_demand(Fn, Subject);
  cfa_parent(ScopeCallee, function(Fn));
  kleo_registered_subjects(ScopeCallee, Subject, Guard);
  cfa_call(ScopeCaller, Fn).
  
%   DEMAND
%===========================================================

%local demand
kleo_scope_demand(Scope, Subject):-         
  not kleo_scope_decision(Scope, Subject, _);
  kleo_registered_subjects(Scope, Subject, Decision).
  
%demand propagation: scope  
kleo_scope_demand(Scope, Subject):-         
  kleo_scope_demand(ScopeChild, Subject);
  cfa_parent(ScopeChild, scope(Scope)).
  
%propagation: interfn  
kleo_fn_demand(Fn, Subject):-
  kleo_scope_demand(ScopeFnBody, Subject);
  cfa_parent(ScopeFnBody, function(Fn)).    
    

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

%local decision
kleo_scope_decision(Scope, Subject, Decision):-     
  bind_scope(Scope, Decision, strong);
  kleo_registered_subjects(Scope, Subject, Decision).

%interfn decision                              
%kleo_scope_decision(ScopeSource, parameter(Subject), Decision):-   
%  weak(bind_scope(Scope, Decision), ScopeSource); 
%  kleo_registered_subjects(Scope, Subject, Decision).