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%  SPDX-FileCopyrightText: 1998-2026 Paulo Moura <pmoura@logtalk.org>
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:- category(attvars).

	:- info([
		version is 1:0:1,
		author is 'Paulo Moura',
		date is 2020-11-15,
		comment is 'Runtime support for attributed variables.'
	]).

	:- public(get_attr/2).
	:- mode(get_attr(@var, -term), one).
	:- info(get_attr/2, [
		comment is 'Description',
		argnames is ['Var', 'Value']
	]).

	:- public(put_attr/2).
	:- mode(put_attr(@var, +term), zero_or_one).
	:- info(put_attr/2, [
		comment is 'Description',
		argnames is ['Var', 'Value']
	]).

	:- public(del_attr/1).
	:- mode(del_attr(@var), one).
	:- info(del_attr/1, [
		comment is 'Description',
		argnames is ['Var']
	]).

	:- if(current_logtalk_flag(prolog_dialect, b)).

		get_attr(Var, Value) :-
			this(This),
			Goal =.. [get_attr, Var, This, Value],
			{Goal}.

		put_attr(Var, Value) :-
			this(This),
			Goal =.. [put_attr, Var, This, Value],
			{Goal}.

		del_attr(Var) :-
			this(This),
			{del_attr(Var, This)}.

	:- elif(current_logtalk_flag(prolog_dialect, xsb)).

		get_attr(Var, Value) :-
			this(This),
			var(Var),
			{get_attr(Var, This, Value)}.

		put_attr(Var, Value) :-
			this(This),
			{put_attr(Var, This, Value)}.

		del_attr(Var) :-
			this(This),
			{del_attr(Var, This)}.

	:- else.

		get_attr(Var, Value) :-
			this(This),
			{get_attr(Var, dispatch, This-Value)}.

		put_attr(Var, Value) :-
			this(This),
			{put_attr(Var, dispatch, This-Value)}.

		del_attr(Var) :-
			{del_attr(Var, dispatch)}.

	:- endif.

:- end_category.