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:- object(fluents).

	:- info([
		version is 1:0:0,
		author is 'Paul Tarau and Paulo Moura',
		date is 2016-06-15,
		comment is 'Examples of implementing fluents using threaded engines.'
	]).

	:- threaded.

	% initialize a fluent and give it a name (which is object-scoped)
	:- initialization(threaded_engine_create(X, a(X), fluent)).

	:- public(next/1).
	:- mode(next(?term), zero_or_one).
	:- info(next/1, [
		comment is 'Returns the next solution for the fluent goal.',
		argnames is ['Next']
	]).

	next(Next) :-
		threaded_engine_next(fluent, Next).

	a(1). a(2). a(3).

:- end_object.
