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yap-6.3/library/dbqueues.yap
2009-06-05 14:31:06 -05:00

53 lines
1.2 KiB
Prolog

% A library to implement queues of NB Terms
:- module(nbqueue, [
nb_enqueue/2,
nb_dequeue/2,
nb_clean_queue/1,
nb_size/2
]).
:- unhide('$init_nb_queue').
:- unhide('$nb_enqueue').
:- unhide('$nb_dequeue').
nb_enqueue(Name,El) :- var(Name),
throw(error(instantiation_error(Name),nb_enqueue(Name,El))).
nb_enqueue(Name,El) :- \+ atom(Name), !,
throw(error(type_error_atom(Name),nb_enqueue(Name,El))).
nb_enqueue(Name,El) :-
recorded('$nb_queue',[Name|Ref],_), !,
prolog:'$nb_enqueue'(Ref, El).
nb_enqueue(Name,El) :-
prolog:'$init_nb_queue'(Ref),
recorda('$nb_queue',[Name|Ref],_),
prolog:'$nb_enqueue'(Ref,El).
nb_dequeue(Name,El) :- var(Name),
throw(error(instantiation_error(Name),nb_dequeue(Name,El))).
nb_dequeue(Name,El) :- \+ atom(Name), !,
throw(error(type_error_atom(Name),nb_dequeue(Name,El))).
nb_dequeue(Name,El) :-
recorded('$nb_queue',[Name|Ref],R),
( prolog:'$nb_dequeue'(Ref, El) ->
true
;
erase(R),
fail
).
nb_clean_queue(Name) :-
recorded('$nb_queue',[Name|Ref],R), !,
erase(R),
nb_dequeue_all(Ref).
nb_clean_queue(_).
nb_dequeue_all(Ref) :-
( prolog:'$nb_dequeue'(Ref, _) -> nb_dequeue_all(Ref) ; true ).
nb_dequeue_size(Ref, Size) :-
prolog:'$nb_size'(Ref, Size).