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

'$parallel_query'(G,[]) :- !, '$start_yapor', '$execute'(G), !, $parallel_yes_answer.
'$parallel_query'(G,V)  :- '$start_yapor', '$execute'(G), $parallel_new_answer(V).

% ***************************
% * -------- YAPOR -------- *
% ***************************

default_sequential(X) :- '$default_sequential'(X), !.
default_sequential(_).

'$sequential' :-
	'$default_sequential'(X),
	'$initialization'('$default_sequential'(X)),
	'$default_sequential'(on).

'$parallel' :-
	'$default_sequential'(X),
	'$initialization'('$default_sequential'(X)),
	'$default_sequential'(off).

'$sequential_directive'(X) :- var(X), !,
                 write(user_error, '[ Error: argument to sequential/1 should be a predicate ]'),
                 nl(user_error),
                 fail.
'$sequential_directive'((A,B)) :- !, sequential(A), sequential(B).
'$sequential_directive'(A/N) :- integer(N), atom(A), !,
                   functor(T,A,N), '$flags'(T,F,F),
                   (
                     X is F /\ 8'000040, X =\= 0, !,
                     write(user_error, '[ Warning: '),
                     write(user_error, A/N),
                     write(user_error, ' is already declared as sequential ]'),
                     nl(user_error)
                   ;
                     X is F /\ 8'170000, X =:= 0, !, '$sequential'(T)
                   ;
                     write(user_error, '[ Error: '),
                     write(user_error, A/N),
                     write(user_error, ' cannot be declared as sequential ]'),
                     nl(user_error),
                     fail
                   ).
'$sequential_directive'(X) :- write(user_error, '[ Error: '),
                 write(user_error, X),
                 write(user_error, ' is an invalid argument to sequential/1 ]'),
                 nl(user_error),
                 fail.

parallel(X) :- var(X), !,
                 write(user_error, '[ Error: argument to parallel/1 should be a predicate ]'),
                 nl(user_error),
                 fail.
parallel((A,B)) :- !, parallel(A), parallel(B).

parallel(A/N) :- integer(N), atom(A), !,
                   functor(T,A,N), '$flags'(T,F,F),
                   (
                     NF is F /\ \(8'000040), '$flags'(T,F,NF) ;
                     write(user_error, '[ Warning: '),
                     write(user_error, A/N),
                     write(user_error, ' is already declared as sequential ]'),
                     nl(user_error)
                   ;
                     X is F /\ 8'170000, X =:= 0, !, $sequential(T)
                   ;
                     write(user_error, '[ Error: '),
                     write(user_error, A/N),
                     write(user_error, ' cannot be declared as parallel ]'),
                     nl(user_error),
                     fail
                   ).
sequential(X) :- write(user_error, '[ Error: '),
                 write(user_error, X),
                 write(user_error, ' is an invalid argument to parallel/1 ]'),
                 nl(user_error),
                 fail.


%
% do not try to run consult in the parallel system.
%
'$parallelizable'(_) :-
	'$get_value'('$consulting_file',S), S\=[], !, fail.
'$parallelizable'((G1,G2)) :- !,
	'$parallelizable'(G1),
	'$parallelizable'(G2).
'$parallelizable'((G1;G2)) :- !,
	'$parallelizable'(G1),
	'$parallelizable'(G2).
'$parallelizable'((G1|G2)) :- !,
	'$parallelizable'(G1),
	'$parallelizable'(G2).
'$parallelizable'((G1->G2)) :- !,
	'$parallelizable'(G1),
	'$parallelizable'(G2).
'$parallelizable'([]) :- !, fail.
'$parallelizable'([_|_]) :- !, fail.
'$parallelizable'(consult(_)) :- !, fail.
'$parallelizable'(reconsult(_)) :- !, fail.
'$parallelizable'(compile(_)) :- !, fail.
'$parallelizable'(use_module(_)) :- !, fail.
'$parallelizable'(_).