eval_call(NewS,_).

max_counting(F,Max):- flag(F,X,X+1),  X<Max ->  true; (flag(F,_,10),!,fail).


% =================================================================
% =================================================================
% =================================================================
%  CONS/DECONS
% =================================================================
% =================================================================
% =================================================================

must_unify(A,A):-!.
must_unify(A,B):- fail, throw('Error-last-form'(must_unify(A,B))). % @TODO

% OLD
eval_20(_Eq,_RetType,_Depth,_Self,['decons-atom',OneArg],_):- OneArg==[], !, fail. %H=[],T=[],!.
eval_20(_Eq,_RetType,_Depth,_Self,['decons-atom',OneArg],[H,T]):- !, must_unify(OneArg,[H|T]).
eval_20(_Eq,_RetType,_Depth,_Self,['cons-atom'|TwoArgs],[H|T]):-!, must_unify(TwoArgs,[H,T]).
% NEW
eval_20(_Eq,_RetType,_Depth,_Self,['decons',OneArg],[H,T]):- !, must_unify(OneArg,[H|T]).
eval_20(_Eq,_RetType,_Depth,_Self,['cons'|TwoArgs],[H|T]):-!, must_unify(TwoArgs,[H,T]).


eval_20(Eq,RetType,Depth,Self,['get-doc'|Args],Res):- !,with_all_spaces(eval_args(Eq,RetType,Depth,Self,['metta-get-doc'|Args],Res)).
eval_20(Eq,RetType,Depth,Self,['help!'|Args],Res):-!,with_all_spaces(eval_args(Eq,RetType,Depth,Self,['metta-help!'|Args],Res)).

with_all_spaces(Goal):-
 locally(nb_setval(with_all_spaces,t),Goal).
using_all_spaces:- nb_current(with_all_spaces,t).

% =================================================================
% =================================================================
% =================================================================
%  if/If
% =================================================================
% =================================================================
% =================================================================

eval_20(Eq,RetType,Depth,Self,['if-unify',X,Y,Then,Else],Res):- !,
   eval_args(Eq,'Bool',Depth,Self,['==',X,Y],TF),
   (is_True(TF)
     -> eval_args(Eq,RetType,Depth,Self,Then,Res)
     ;  eval_args(Eq,RetType,Depth,Self,Else,Res)).


eval_20(Eq,RetType,Depth,Self,['if-equal',X,Y,Then,Else],Res):- !,

   ( \+ \+ (eval_args(Eq,'Bool',Depth,Self,['==',X,Y],TF),is_True(TF))
     -> eval_args(Eq,RetType,Depth,Self,Then,Res)
     ;  eval_args(Eq,RetType,Depth,Self,Else,Res)).


eval_20(Eq,RetType,Depth,Self,['if',Cond,Then,Else],Res):- !,
   eval_args(Eq,'Bool',Depth,Self,Cond,TF),
   (is_True(TF)
     -> eval_args(Eq,RetType,Depth,Self,Then,Res)
     ;  eval_args(Eq,RetType,Depth,Self,Else,Res)).

eval_20(Eq,RetType,Depth,Self,['If',Cond,Then,Else],Res):- !,
   eval_args(Eq,'Bool',Depth,Self,Cond,TF),
   (is_True(TF)
     -> eval_args(Eq,RetType,Depth,Self,Then,Res)
     ;  eval_args(Eq,RetType,Depth,Self,Else,Res)).

eval_20(Eq,RetType,Depth,Self,['If',Cond,Then],Res):- !,
   eval_args(Eq,'Bool',Depth,Self,Cond,TF),