/*************************************************************************
*									 *
*	 YAP Prolog 							 *
*									 *
*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
*									 *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
*									 *
**************************************************************************
*									 *
* File:		preds.yap						 *
* Last rev:	8/2/88							 *
* mods:									 *
* comments:	Predicate Manipulation for YAP: declaration support	 *
*									 *
*************************************************************************/

:- system_module( '$_preddecls', [(discontiguous)/1,
        (dynamic)/1,
        (multifile)/1], ['$check_multifile_pred'/3,
        '$discontiguous'/2,
        '$dynamic'/2]).

:- use_system_module( '$_consult', ['$add_multifile'/3]).

:- use_system_module( '$_errors', ['$do_error'/2]).

%
% can only do as goal in YAP mode.
%
dynamic(X) :- '$access_yap_flags'(8, 0), !,
        '$current_module'(M),
	'$dynamic'(X, M).
dynamic(X) :-
	'$do_error'(context_error(dynamic(X),declaration),query).

'$dynamic'(X,M) :- var(X), !,
	'$do_error'(instantiation_error,dynamic(M:X)).
'$dynamic'(Mod:Spec,_) :- !,
	'$dynamic'(Spec,Mod).
'$dynamic'([], _) :- !.
'$dynamic'([H|L], M) :- !, '$dynamic'(H, M), '$dynamic'(L, M).
'$dynamic'((A,B),M) :- !, '$dynamic'(A,M), '$dynamic'(B,M).
'$dynamic'(X,M) :-
	'$dynamic2'(X,M).

'$dynamic2'(X, Mod) :- '$log_upd'(Stat), Stat\=0, !,
	'$logical_updatable'(X, Mod).
'$dynamic2'(A//N1, Mod) :-
	integer(N1),
	N is N1+2,
	'$dynamic2'(A/N, Mod).
'$dynamic2'(A/N, Mod) :-
	integer(N), atom(A), !,
	functor(T,A,N), '$flags'(T,Mod,F,F),
	% LogUpd,BinaryTest,Safe,C,Dynamic,Compiled,Standard,Asm,
	( F/\ 0x19D1FA80 =:= 0, '$undefined'(T,Mod) -> NF is F \/ 0x00002000, '$flags'(T, Mod, F, NF), '$mk_d'(T,Mod);
	    F /\ 0x00002000 =:= 0x00002000 -> '$mk_d'(T,Mod);                     % dynamic
	    F /\ 0x08000000 =:= 0x08000000 -> '$mk_d'(T,Mod) ;      % LU
	    F /\ 0x00000400 =:= 0x00000400, '$undefined'(T,Mod) -> F1 is F /\ \(0x400), N1F is F1 \/ 0x00002000, NF is N1F /\ \(0x00400000), '$flags'(T,Mod,F,NF), '$mk_d'(T,Mod);
	    '$do_error'(permission_error(modify,static_procedure,A/N),dynamic(Mod:A/N))
	).
'$dynamic2'(X,Mod) :- 
	'$do_error'(type_error(callable,X),dynamic(Mod:X)).

'$logical_updatable'(A//N,Mod) :- integer(N), !,
	N1 is N+2,
	'$logical_updatable'(A/N1,Mod).
'$logical_updatable'(A/N,Mod) :- integer(N), atom(A), !,
	functor(T,A,N), '$flags'(T,Mod,F,F),
	(
	    F/\ 0x19D1FA80 =:= 0, '$undefined'(T,Mod) -> NF is F \/ 0x08000400, '$flags'(T,Mod,F,NF), '$mk_d'(T,Mod);
	    F /\ 0x08000000 =:= 0x08000000 -> '$mk_d'(T,Mod) ;      % LU
	    F /\ 0x00002000 =:= 0x00002000 -> '$mk_d'(T,Mod);      % dynamic
	    F /\ 0x00000400 =:= 0x00000400 , '$undefined'(T,Mod) -> N1F is F \/ 0x08000000, NF is N1F /\ \(0x00400000), '$flags'(T,Mod,F,NF), '$mk_d'(T,Mod);
	    '$do_error'(permission_error(modify,static_procedure,A/N),dynamic(Mod:A/N))
	).
'$logical_updatable'(X,Mod) :- 
	'$do_error'(type_error(callable,X),dynamic(Mod:X)).

multifile(P) :-
	'$current_module'(OM),
	'$multifile'(P, M).

'$multifile'(V, _) :- var(V), !,
	'$do_error'(instantiation_error,multifile(V)).
'$multifile'((X,Y), M) :- !, '$multifile'(X, M), '$multifile'(Y, M).
'$multifile'(Mod:PredSpec, _) :- !,
	'$multifile'(PredSpec, Mod).
'$multifile'(N//A, M) :- !,
	integer(A),
	A1 is A+2,
	'$multifile'(N/A1, M).
'$multifile'(N/A, M) :-
	'$add_multifile'(N,A,M),
	fail.
'$multifile'(N/A, M) :-
         functor(S,N,A),
	'$is_multifile'(S, M), !.
'$multifile'(N/A, M) :- !,
	'$new_multifile'(N,A,M).
'$multifile'([H|T], M) :- !,
	'$multifile'(H,M),
	'$multifile'(T,M).
'$multifile'(P, M) :-
	'$do_error'(type_error(predicate_indicator,P),multifile(M:P)).

discontiguous(V) :-
	var(V), !,
	'$do_error'(instantiation_error,discontiguous(V)).
discontiguous(M:F) :- !,
	'$discontiguous'(F,M).
discontiguous(F) :-
	'$current_module'(M),
	'$discontiguous'(F,M).

'$discontiguous'(V,M) :- var(V), !,
	'$do_error'(instantiation_error,M:discontiguous(V)).
'$discontiguous'((X,Y),M) :- !,
	'$discontiguous'(X,M),
	'$discontiguous'(Y,M).
'$discontiguous'(M:A,_) :- !,
	'$discontiguous'(A,M).
'$discontiguous'(N//A1, M) :- !,
	integer(A1), !,
	A is A1+2,
	'$discontiguous'(N/A, M).
'$discontiguous'(N/A, M) :- !,
	( recordzifnot('$discontiguous_defs','$df'(N,A,M),_) ->
	    true
	;
	    true
	).
'$discontiguous'(P,M) :-
	'$do_error'(type_error(predicate_indicator,P),M:discontiguous(P)).

%
% did we declare multifile properly?
%
'$check_multifile_pred'(Hd, M, _) :-
	functor(Hd,Na,Ar),
	source_location(F, _),
	recorded('$multifile_defs','$defined'(F,Na,Ar,M),_), !.
% oops, we did not.
'$check_multifile_pred'(Hd, M, Fl) :-
	% so this is not a multi-file predicate any longer.
	functor(Hd,Na,Ar),
	NFl is \(0x20000000) /\ Fl,
	'$flags'(Hd,M,Fl,NFl),
	'$warn_mfile'(Na,Ar).

'$warn_mfile'(F,A) :-
	write(user_error,'% Warning: predicate '),
	write(user_error,F/A), write(user_error,' was a multifile predicate '),
	write(user_error,' (line '),
	'$start_line'(LN), write(user_error,LN),
	write(user_error,')'),
	nl(user_error).