%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  Adapter file for SWI Prolog 6.6.0 and later versions
%  Last updated on March 25, 2026
%
%  This file is part of Logtalk <https://logtalk.org/>
%  SPDX-FileCopyrightText: 1998-2026 Paulo Moura <pmoura@logtalk.org>
%  SPDX-License-Identifier: Apache-2.0
%
%  Licensed under the Apache License, Version 2.0 (the "License");
%  you may not use this file except in compliance with the License.
%  You may obtain a copy of the License at
%
%      http://www.apache.org/licenses/LICENSE-2.0
%
%  Unless required by applicable law or agreed to in writing, software
%  distributed under the License is distributed on an "AS IS" BASIS,
%  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%  See the License for the specific language governing permissions and
%  limitations under the License.
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% the following flag controls output of SWI-Prolog specific source location
% information when writing the intermediate Prolog files generated by the
% compilation of Logtalk source files; setting this flag to "true" is
% required for integration with some SWI-Prolog developer tools such as
% the graphical tracer; see the `samples/settings-sample.lgt` file for details
:- create_prolog_flag(logtalk_source_location_data, false, []).


:- set_prolog_flag(generate_debug_info, false).
% the following directive is commented due to all the SWI-Prolog
% libraries that don't compile/work in "iso" mode
%:- set_prolog_flag(iso, true).


% disable SWI-Prolog discontiguous predicate clauses warning
% as the Logtalk compiler does its own detection and there's
% no point in printing the same warning twice
%
%:- multifile(message_hook/3).
%:- dynamic(message_hook/3).
%message_hook(discontiguous(_), _, _).


:- if(\+ license:license(asl2, _, _)).
	:- multifile(license:license/3).
	license:license(asl2, permissive, [
		comment('Apache License 2.0'),
		url('http://www.apache.org/licenses/LICENSE-2.0')
	]).
:- endif.

:- license(asl2, 'Logtalk').


:- if(exists_source(library(prolog_evaluable))).
	:- use_module(library(prolog_evaluable), [evaluable_property/2]).
:- endif.



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  ISO Prolog Standard predicates that we must define because they are
%  not built-in
%
%  add a clause for '$lgt_iso_predicate'/1 declaring each ISO predicate that
%  we must define; there must be at least one clause for this predicate
%  whose call should fail if we don't define any ISO predicates
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_iso_predicate'(?callable).

'$lgt_iso_predicate'(_) :-
	fail.



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  de facto standard Prolog predicates that might be missing
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% between(+integer, +integer, ?integer) -- built-in


% findall(?term, +callable, ?list, +list) -- built-in


% forall(+callable, +callable) -- built-in


% format(+stream_or_alias, +character_code_list_or_atom, +list) -- built-in

'$lgt_format'(Stream, Format, Arguments) :-
	format(Stream, Format, Arguments).

'$lgt_format'(Format, Arguments) :-
	format(Format, Arguments).


% format(+character_code_list_or_atom, +list) -- built-in


% numbervars(?term, +integer, ?integer) -- built-in



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  predicate properties
%
%  this predicate must return at least static, dynamic, and built_in
%  properties for an existing predicate (and ideally meta_predicate/1
%  properties for built-in predicates and library predicates)
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_predicate_property'(+callable, ?predicate_property)

'$lgt_predicate_property'(Pred, Prop) :-
	% avoid calls to predicate_property/2 triggering library auto-loading
	% (as this could introduce unwanted dependencies) by calling
	% current_predicate/1 first (which never triggers auto-loading)
	(	Pred = Module:Callable ->
		functor(Callable, Functor, Arity),
		current_predicate(Module:Functor/Arity)
	;	functor(Pred, Functor, Arity),
		current_predicate(Functor/Arity)
	),
	predicate_property(Pred, Prop).


% SWI-Prolog provides a sleep/1 predicate instead of the thread_sleep/1
% predicate specified in the ISO Prolog Threads standardization proposal;
% we simply defined this predicate later this file and pretend that it's
% a built-in predicate
'$lgt_predicate_property'(thread_sleep(_), built_in).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  meta-predicates
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% setup_call_cleanup(+callable, +callable, +callable) -- built-in



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  Prolog non-standard built-in meta-predicates and meta-directives
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_prolog_meta_predicate'(@callable, ?callable, ?atom)
%
% table of meta-predicate patterns for proprietary built-in predicates;
% the third argument, which must be either "predicate" or "control_construct",
% is used to guide the compilation of these meta-predicates in debug mode

'$lgt_prolog_meta_predicate'(*->(_, _), *->(0, 0), control_construct).
:- if(predicate_property(block(_, _, _), built_in)).
	'$lgt_prolog_meta_predicate'(block(_, _, _), block(*, 0, *), predicate).
:- endif.
'$lgt_prolog_meta_predicate'(call_cleanup(_, _), call_cleanup(0, 0), predicate).
'$lgt_prolog_meta_predicate'(call_cleanup(_, _, _), call_cleanup(0, *, 0), predicate).
'$lgt_prolog_meta_predicate'(call_with_depth_limit(_, _, _), call_with_depth_limit(0, *, *), predicate).
'$lgt_prolog_meta_predicate'(call_with_inference_limit(_, _, _), call_with_inference_limit(0, *, *), predicate).
'$lgt_prolog_meta_predicate'(compile_predicates(_), compile_predicates([/]), predicate).
'$lgt_prolog_meta_predicate'(dynamic(_), dynamic(/), predicate).
'$lgt_prolog_meta_predicate'(findall(_, _, _, _), findall(*, 0, *, *), predicate).
'$lgt_prolog_meta_predicate'(freeze(_, _), freeze(*, 0), predicate).
'$lgt_prolog_meta_predicate'(multifile(_), multifile(/), predicate).
'$lgt_prolog_meta_predicate'(not(_), not(0), predicate).
'$lgt_prolog_meta_predicate'(notrace(_), notrace(0), predicate).
'$lgt_prolog_meta_predicate'(on_signal(_, _, _), on_signal(*, *, 0), predicate).
'$lgt_prolog_meta_predicate'(setup_call_cleanup(_, _, _), setup_call_cleanup(0, 0, 0), predicate).
'$lgt_prolog_meta_predicate'(setup_call_catcher_cleanup(_, _, _, _), setup_call_catcher_cleanup(0, 0, *, 0), predicate).
'$lgt_prolog_meta_predicate'(thread_initialization(_), thread_initialization(0), predicate).
'$lgt_prolog_meta_predicate'(thread_at_exit(_), thread_at_exit(0), predicate).
'$lgt_prolog_meta_predicate'(thread_create(_, _, _), thread_create(0, *, *), predicate).
'$lgt_prolog_meta_predicate'(thread_signal(_, _), thread_signal(*, 0), predicate).
'$lgt_prolog_meta_predicate'(trace(_), trace(0), predicate).
'$lgt_prolog_meta_predicate'(trace(_, _), trace(0, *), predicate).
:- if(predicate_property(win_insert_menu_item(_, _, _, _), built_in)).
	'$lgt_prolog_meta_predicate'(win_insert_menu_item(_, _, _, _), win_insert_menu_item(*, *, *, 0), predicate).
:- endif.
'$lgt_prolog_meta_predicate'(with_mutex(_, _), with_mutex(*, 0), predicate).
'$lgt_prolog_meta_predicate'(with_output_to(_, _), with_output_to(*, 0), predicate).
% workaround problematic meta-predicate declarations:
'$lgt_prolog_meta_predicate'(consult(_), consult(*), predicate).
'$lgt_prolog_meta_predicate'(current_op(_, _, _), current_op(*, *, *), predicate).
'$lgt_prolog_meta_predicate'(ensure_loaded(_), ensure_loaded(*), predicate).
'$lgt_prolog_meta_predicate'(format(_, _), format(*, *), predicate).
'$lgt_prolog_meta_predicate'(format(_, _, _), format(*, *, *), predicate).
'$lgt_prolog_meta_predicate'(load_files(_), load_files(*), predicate).
'$lgt_prolog_meta_predicate'(load_files(_, _), load_files(*, *), predicate).
'$lgt_prolog_meta_predicate'(op(_, _, _), op(*, *, *), predicate).
:- if(predicate_property(table(_), built_in)).
	'$lgt_prolog_meta_predicate'(table(_), table(/), predicate).
:- endif.
:- if(predicate_property(tnot(_), built_in)).
	'$lgt_prolog_meta_predicate'(tnot(_), tnot(0), predicate).
:- endif.
:- if(predicate_property(untable(_), built_in)).
	'$lgt_prolog_meta_predicate'(untable(_), untable(/), predicate).
:- endif.
'$lgt_prolog_meta_predicate'(use_module(_), use_module(*), predicate).
'$lgt_prolog_meta_predicate'(use_module(_, _), use_module(*, *), predicate).


% '$lgt_prolog_meta_directive'(@callable, -callable)

'$lgt_prolog_meta_directive'(at_halt(_), at_halt(0)).
'$lgt_prolog_meta_directive'(format_predicate(_, _), format_predicate(*, 0)).
'$lgt_prolog_meta_directive'(initialization(_, _), initialization(0, *)).
'$lgt_prolog_meta_directive'(noprofile(_), noprofile(/)).
:- if(predicate_property(table(_), built_in)).
	'$lgt_prolog_meta_directive'(table(_), table(/)).
:- endif.
'$lgt_prolog_meta_directive'(thread_initialization(_), thread_initialization(0)).
'$lgt_prolog_meta_directive'(thread_local(_), thread_local(/)) :-
	logtalk_load_context(entity_type, Type),
	Type \== module.
'$lgt_prolog_meta_directive'(volatile(_), volatile(/)).


% '$lgt_prolog_to_logtalk_meta_argument_specifier_hook'(@nonvar, -atom)

'$lgt_prolog_to_logtalk_meta_argument_specifier_hook'((//), 2).


% '$lgt_prolog_phrase_predicate'(@callable)
%
% table of predicates that call non-terminals
% (other than the de facto standard phrase/2-3 predicates)

'$lgt_prolog_phrase_predicate'(call_dcg(_, _, _)).
'$lgt_prolog_phrase_predicate'(pio:phrase_from_file(_, _)).
'$lgt_prolog_phrase_predicate'(pio:phrase_from_file(_, _, _)).
'$lgt_prolog_phrase_predicate'(pio:phrase_from_stream(_, _)).
'$lgt_prolog_phrase_predicate'(pure_input:phrase_from_file(_, _)).
'$lgt_prolog_phrase_predicate'(pure_input:phrase_from_file(_, _, _)).
'$lgt_prolog_phrase_predicate'(pure_input:phrase_from_stream(_, _)).



% '$lgt_candidate_tautology_or_falsehood_goal_hook'(@callable)
%
% valid candidates are proprietary built-in predicates with no
% side-effects when called with ground arguments

'$lgt_candidate_tautology_or_falsehood_goal_hook'(_ =@= _).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(_ \=@= _).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(?=(_, _)).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(atom_number(_, _)).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(atom_string(_, _)).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(cyclic_term(_)).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(name(_, _)).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(number_string(_, _)).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(plus(_, _, _)).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(rational(_)).
'$lgt_candidate_tautology_or_falsehood_goal_hook'(succ(_, _)).


% '$lgt_prolog_database_predicate'(@callable)
%
% table of non-standard database built-in predicates

'$lgt_prolog_database_predicate'(assert(_)).
'$lgt_prolog_database_predicate'(assert(_, _)).
'$lgt_prolog_database_predicate'(asserta(_, _)).
'$lgt_prolog_database_predicate'(assertz(_, _)).
'$lgt_prolog_database_predicate'(clause(_, _, _)).
'$lgt_prolog_database_predicate'(listing(_)).


% '$lgt_prolog_predicate_property'(?callable)
%
% table of proprietary predicate properties; used by the
% compiler when checking if a predicate property is valid

'$lgt_prolog_predicate_property'(discontiguous).
'$lgt_prolog_predicate_property'(indexed(_)).
'$lgt_prolog_predicate_property'(monotonic).
'$lgt_prolog_predicate_property'(opaque).
'$lgt_prolog_predicate_property'(tabled).
'$lgt_prolog_predicate_property'(tabled(_)).
'$lgt_prolog_predicate_property'(thread_local).
'$lgt_prolog_predicate_property'(volatile).


% '$lgt_prolog_deprecated_built_in_predicate_hook'(?callable, ?callable)
%
% table of proprietary deprecated built-in predicates
% when there's a Prolog system advised alternative

'$lgt_prolog_deprecated_built_in_predicate_hook'(_, _) :-
	fail.


% '$lgt_prolog_deprecated_built_in_predicate_hook'(?callable)
%
% table of proprietary deprecated built-in predicates without
% a direct advised alternative

'$lgt_prolog_deprecated_built_in_predicate_hook'(_) :-
	fail.



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  file name extension predicates
%
%  these extensions are used by Logtalk load/compile predicates
%
%  you may want to change the extension for the intermediate files
%  generated by the Logtalk compiler ("object" files) to match the
%  extension expected by default by your Prolog compiler
%
%  there should only a single extension defined for object files but
%  but multiple extensions can be defined for Logtalk and Prolog source
%  files and for backend specific temporary files
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_file_extension'(?atom, ?atom)

'$lgt_file_extension'(logtalk, '.lgt').
'$lgt_file_extension'(logtalk, '.logtalk').
% there must be a single object file extension
'$lgt_file_extension'(object, '.pl').
'$lgt_file_extension'(prolog, '.pl').
'$lgt_file_extension'(prolog, '.prolog').
'$lgt_file_extension'(prolog, '.pro').
'$lgt_file_extension'(tmp, '.qlf').



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  backend Prolog compiler features
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_prolog_feature'(?atom, ?atom)
%
% backend Prolog compiler supported features (that are compatible with Logtalk)

'$lgt_prolog_feature'(prolog_dialect, swi).
'$lgt_prolog_feature'(prolog_version, v(Major, Minor, Patch)) :-
	current_prolog_flag(version_data, swi(Major, Minor, Patch, _)).
'$lgt_prolog_feature'(prolog_compatible_version, @>=(v(6,6,0))).

'$lgt_prolog_feature'(encoding_directive, full).
'$lgt_prolog_feature'(tabling, Tabling) :-
	current_prolog_flag(version_data, swi(Major, Minor, Patch, _)),
	(	(Major,Minor,Patch) @>= (7,3,21) ->
		Tabling = supported
	;	Tabling = unsupported
	).
'$lgt_prolog_feature'(engines, Engines) :-
	(	current_prolog_flag(threads, true) ->
		Engines = supported,
		volatile('$lgt_current_engine_'/4)
	;	Engines = unsupported
	).
'$lgt_prolog_feature'(threads, Threads) :-
	(	current_prolog_flag(threads, true) ->
		Threads = supported
	;	Threads = unsupported
	).
'$lgt_prolog_feature'(modules, supported).
'$lgt_prolog_feature'(coinduction, supported).
'$lgt_prolog_feature'(unicode, full).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  default flag values
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_default_flag'(?atom, ?atom)
%
% default values for all flags

% startup flags:
'$lgt_default_flag'(settings_file, allow).
% lint compilation flags:
'$lgt_default_flag'(linter, default).
'$lgt_default_flag'(general, warning).
'$lgt_default_flag'(encodings, warning).
'$lgt_default_flag'(unknown_entities, warning).
'$lgt_default_flag'(unknown_predicates, warning).
'$lgt_default_flag'(undefined_predicates, warning).
'$lgt_default_flag'(singleton_variables, warning).
'$lgt_default_flag'(steadfastness, silent).
'$lgt_default_flag'(naming, silent).
'$lgt_default_flag'(duplicated_clauses, silent).
'$lgt_default_flag'(left_recursion, warning).
'$lgt_default_flag'(tail_recursive, silent).
'$lgt_default_flag'(disjunctions, warning).
'$lgt_default_flag'(conditionals, warning).
'$lgt_default_flag'(catchall_catch, silent).
'$lgt_default_flag'(portability, silent).
'$lgt_default_flag'(redefined_built_ins, silent).
'$lgt_default_flag'(redefined_operators, warning).
'$lgt_default_flag'(deprecated, warning).
'$lgt_default_flag'(missing_directives, warning).
'$lgt_default_flag'(duplicated_directives, warning).
'$lgt_default_flag'(trivial_goal_fails, warning).
'$lgt_default_flag'(always_true_or_false_goals, warning).
'$lgt_default_flag'(lambda_variables, warning).
'$lgt_default_flag'(grammar_rules, warning).
'$lgt_default_flag'(arithmetic_expressions, warning).
'$lgt_default_flag'(suspicious_calls, warning).
'$lgt_default_flag'(underscore_variables, dont_care).
% optional features compilation flags:
'$lgt_default_flag'(complements, deny).
'$lgt_default_flag'(dynamic_declarations, deny).
'$lgt_default_flag'(events, deny).
'$lgt_default_flag'(context_switching_calls, allow).
% other compilation flags:
'$lgt_default_flag'(scratch_directory, ScratchDirectory) :-
	(	current_prolog_flag(unix, true) ->
		ScratchDirectory = './.lgt_tmp/'
	;	ScratchDirectory = './lgt_tmp/'
	).
'$lgt_default_flag'(report, Report) :-
	(	current_prolog_flag(verbose, silent) ->
		Report = warnings
	;	Report = on
	).
'$lgt_default_flag'(clean, on).
'$lgt_default_flag'(code_prefix, '$').
'$lgt_default_flag'(optimize, off).
'$lgt_default_flag'(source_data, on).
'$lgt_default_flag'(reload, changed).
'$lgt_default_flag'(debug, off).
% Prolog compiler and loader flags:
'$lgt_default_flag'(prolog_compiler, []).
'$lgt_default_flag'(prolog_loader, [silent(true), optimise(true)]).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  operating-system access predicates
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_prolog_os_file_name'(+atom, -atom)
% '$lgt_prolog_os_file_name'(-atom, +atom)
%
% converts between Prolog internal file paths and operating-system paths

'$lgt_prolog_os_file_name'(PrologPath, OSPath) :-
	prolog_to_os_filename(PrologPath, OSPath).


% '$lgt_expand_path'(+atom, -atom)
%
% expands a file path to a full path

'$lgt_expand_path'(Path, ExpandedPath) :-
	working_directory(Current, Current),
	(	absolute_file_name(Path, [expand(true), relative_to(Current), file_errors(fail)], ExpandedPath) ->
		true
	;	absolute_file_name(Path, [expand(true), relative_to(Current), file_type(directory), file_errors(fail)], ExpandedPath)
	).


% '$lgt_file_exists'(+atom)
%
% checks if a file exists

'$lgt_file_exists'(File) :-
	exists_file(File).


% '$lgt_delete_file'(+atom)
%
% deletes a file

'$lgt_delete_file'(File) :-
	delete_file(File).


% '$lgt_directory_exists'(+atom)
%
% checks if a directory exists

'$lgt_directory_exists'(Directory) :-
	expand_file_name(Directory, [Path]),
	exists_directory(Path).


% '$lgt_current_directory'(-atom)
%
% gets current working directory

'$lgt_current_directory'(Directory) :-
	working_directory(Directory, Directory).


% '$lgt_change_directory'(+atom)
%
% changes current working directory

'$lgt_change_directory'(Directory) :-
	% fix possible mix of forward and backward slashes
	prolog_to_os_filename(Directory, Path),
	% expand environment variables
	expand_file_name(Path, [Expanded]),
	% convert to SWI-Prolog notation for paths
	prolog_to_os_filename(Fixed, Expanded),
	working_directory(_, Fixed).


% '$lgt_make_directory'(+atom)
%
% makes a new directory; succeeds if the directory already exists

'$lgt_make_directory'(Directory) :-
	% fix possible mix of forward and backward slashes
	prolog_to_os_filename(Directory, Path),
	% expand environment variables
	expand_file_name(Path, [Expanded]),
	% convert to SWI-Prolog notation for paths
	prolog_to_os_filename(Fixed, Expanded),
	(	exists_directory(Fixed) ->
		true
	;	make_directory(Fixed)
	).


% '$lgt_directory_hashes'(+atom, -atom, -atom)
%
% returns the directory hash and dialect as an atom with the format _hash_dialect
% plus the the directory hash and PID as an atom with the format _hash_pid

'$lgt_directory_hashes'(Directory, HashDialect, HashPid) :-
	term_hash(Directory, Hash),
	'$lgt_prolog_feature'(prolog_dialect, Dialect),
	current_prolog_flag(pid, PID),
	atomic_list_concat(['_', Hash, '_', Dialect], HashDialect),
	atomic_list_concat(['_', Hash, '_', PID], HashPid).


% '$lgt_compile_prolog_code'(+atom, +atom, +list)
%
% compile to disk a Prolog file, resulting from a
% Logtalk source file, given a list of flags

'$lgt_compile_prolog_code'(_, _, _).


% '$lgt_load_prolog_code'(+atom, +atom, +list)
%
% compile and load a Prolog file, resulting from a
% Logtalk source file, given a list of flags

'$lgt_load_prolog_code'(File, Source, Options) :-
	% only record the "derived from" information between the Logtalk
	% source file and the generated intermediate Prolog file when
	% integrating with the SWI-Prolog developer tools
	(	current_prolog_flag(logtalk_source_location_data, true) ->
		LoadOptions = [derived_from(Source)| Options]
	;	LoadOptions = Options
	),
	% remove the Prolog file name extension in order to support generating
	% and loading of .qlf files when using the qcompile/1 option
	file_name_extension(Path, _, File),
	(	style_check('?'(singleton)) ->
		% turn off singleton variable checking as the built-in
		% write_canonical/2 predicate can generate code that
		% triggers the new singleton analysis introduced in
		% SWI-Prolog 6.5.0
		setup_call_cleanup(
			style_check('-'(singleton)),
			load_files(Path, LoadOptions),
			style_check('+'(singleton))
		)
	;	load_files(Path, LoadOptions)
	).


% '$lgt_load_prolog_file'(+atom)
%
% compile and (re)load a Prolog file (used in standards compliance tests)

'$lgt_load_prolog_file'(File) :-
	load_files(File).


% '$lgt_file_modification_time'(+atom, -nonvar)
%
% gets a file modification time, assumed to be an opaque term but comparable

'$lgt_file_modification_time'(File, Time) :-
	time_file(File, Time).


% '$lgt_environment_variable'(?atom, ?atom)
%
% access to operating-system environment variables

'$lgt_environment_variable'(Variable, Value) :-
	getenv(Variable, Value).


% '$lgt_decompose_file_name'(+atom, ?atom, ?atom, ?atom)
%
% decomposes a file path in its components; the directory must always end
% with a slash; the extension must start with a "." when defined and must
% be the empty atom when it does not exist

'$lgt_decompose_file_name'(File, Directory, Name, Extension) :-
	file_directory_name(File, Directory0),
	atom_concat(Directory0, '/', Directory),
	file_base_name(File, Basename),
	file_name_extension(Name, Extension0, Basename),
	(	Extension0 = '' ->
		Extension = Extension0
	;	atom_concat('.', Extension0, Extension)
	).


% '$lgt_directory_files'(+atom, -list(atom))
%
% returns a list of files in the given directory

'$lgt_directory_files'(Directory, Files) :-
	directory_files(Directory, Files).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  getting stream current line number
%  (needed for improved compiler error messages)
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_stream_current_line_number'(@stream, -integer)

'$lgt_stream_current_line_number'(Stream, Line) :-
	stream_property(Stream, position(Position)),
	stream_position_data(line_count, Position, Line).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  abstraction of the standard open/4 and close/1 predicates for dealing
%  with required proprietary actions when opening and closing streams
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_open'(+atom, +atom, -stream, @list)
% '$lgt_close'(@stream)

:- if(predicate_property('$push_input_context'(_), built_in)).

	'$lgt_open'(File, Mode, Stream, Options) :-
		open(File, Mode, Stream, Options),
		'$push_input_context'(logtalk).

	'$lgt_close'(Stream) :-
		'$pop_input_context',
		close(Stream).

:- else.

	'$lgt_open'(File, Mode, Stream, Options) :-
		open(File, Mode, Stream, Options).

	'$lgt_close'(Stream) :-
		close(Stream).

:- endif.



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  customized version of the read_term/3 predicate for returning the term
%  position (start and end lines; needed for improved error messages) due
%  to the lack of a standard option for this purpose
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_read_term'(@stream, -term, +list, -pair(integer,integer))

'$lgt_read_term'(Stream, Term, Options, LineBegin-LineEnd) :-
	read_term(Stream, Term, [term_position(PositionBegin), syntax_errors(error)| Options]),
	stream_position_data(line_count, PositionBegin, LineBegin),
	stream_property(Stream, position(PositionEnd)),
	stream_position_data(line_count, PositionEnd, LineEnd).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  Prolog dialect specific term and goal expansion
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_prolog_term_expansion'(@callable, -callable)

'$lgt_prolog_term_expansion'((:- Directive), Expanded) :-
	nonvar(Directive),
	% allow first-argument indexing
	catch('$lgt_swi_directive_expansion'(Directive, Expanded), _, fail).


'$lgt_swi_directive_expansion'(public(_), []) :-
	% used to provide information about module predicates to the cross-referencer
	logtalk_load_context(entity_type, module).

'$lgt_swi_directive_expansion'(style_check(Option), []) :-
	style_check(Option).

'$lgt_swi_directive_expansion'(arithmetic_function(Functor/Arity), {:- arithmetic_function(Functor/Arity)}) :-
	logtalk_load_context(entity_type, _),
	'$lgt_compile_predicate_indicators'(Functor/Arity, _, TFunctor/TArity),
	functor(Term, Functor, TArity),
	Term =.. [_| Args],
	TArity2 is TArity + 1,
	functor(TTerm, TFunctor, TArity2),
	TTerm =.. [_| TArgs],
	'$lgt_swi_unify_head_thead_args'(Args, TArgs),
	'$lgt_compile_aux_clauses'([({Term} :- {TTerm})]).

'$lgt_swi_directive_expansion'(create_prolog_flag(Key, Value, Options), {:- create_prolog_flag(Key, Value, Options)}).

'$lgt_swi_directive_expansion'(expects_dialect(Dialect), {:- expects_dialect(Dialect)}) :-
	expects_dialect(Dialect).

'$lgt_swi_directive_expansion'(license(License), {:- license(License)}).

'$lgt_swi_directive_expansion'(set_prolog_flag(generate_debug_info, false), {:- set_prolog_flag(generate_debug_info, false)}).

'$lgt_swi_directive_expansion'(use_foreign_library(File), {:- use_foreign_library(File)}) :-
	load_foreign_library(File).

'$lgt_swi_directive_expansion'(use_foreign_library(File, Entry), {:- use_foreign_library(File, Entry)}) :-
	load_foreign_library(File, Entry).

'$lgt_swi_directive_expansion'(encoding(Encoding1), (:- encoding(Encoding2))) :-
	nonvar(Encoding1),
	'$lgt_swi_encoding_to_logtalk_encoding'(Encoding1, Encoding2).

'$lgt_swi_directive_expansion'(ensure_loaded(File), Expanded) :-
	logtalk_load_context(entity_type, module),
	% ensure_loaded/1 directive used within a module
	% (sloppy replacement for the use_module/1-2 directives)
	'$lgt_swi_directive_expansion'(use_module(File), Expanded).

'$lgt_swi_directive_expansion'(op(Priority, Specifier, Module:Operators), {:- op(Priority, Specifier, Operators)}) :-
	Module == user.

'$lgt_swi_directive_expansion'(use_module(File, Imports0), (:- use_module(Module, Imports))) :-
	logtalk_load_context(entity_type, module),
	% we're compiling a module as an object; assume referenced modules are also compiled as objects
	!,
	'$lgt_swi_list_of_exports'(File, Module, Exports),
	'$lgt_swi_filter_imports'(Imports0, Exports, Imports1),
	'$lgt_swi_fix_predicate_aliases'(Imports1, Imports).

'$lgt_swi_directive_expansion'(use_module(File, Imports0), [{:- use_module(File, Imports0)}, (:- use_module(Module, Imports))]) :-
	logtalk_load_context(entity_type, _),
	% object or category using a Prolog module
	'$lgt_swi_list_of_exports'(File, Module, Exports),
	'$lgt_swi_filter_imports'(Imports0, Exports, Imports1),
	'$lgt_swi_fix_predicate_aliases'(Imports1, Imports),
	use_module(File, Imports0).

'$lgt_swi_directive_expansion'(use_module(File), []) :-
	logtalk_load_context(entity_type, module),
	% we're compiling a module as an object
	File == library(yall),
	% library(yall) implements Logtalk's lambda expressions
	!.

'$lgt_swi_directive_expansion'(use_module(File), (:- use_module(Module, Imports))) :-
	File \= [_| _],
	% not the Logtalk use_module/1 directive
	logtalk_load_context(entity_type, module),
	% we're compiling a module as an object;
	% assume referenced modules are also compiled as objects
	!,
	'$lgt_swi_list_of_exports'(File, Module, Imports).

'$lgt_swi_directive_expansion'(use_module(File), [{:- use_module(File)}, (:- use_module(Module, Imports))]) :-
	File \= [_| _],
	% not the Logtalk use_module/1 directive
	logtalk_load_context(entity_type, _),
	% object or category using a Prolog module
	'$lgt_swi_list_of_exports'(File, Module, Imports),
	use_module(File).

'$lgt_swi_directive_expansion'(autoload(File, Imports), Expansion) :-
	'$lgt_swi_directive_expansion'(use_module(File, Imports), Expansion).

'$lgt_swi_directive_expansion'(autoload(File), Expansion) :-
	'$lgt_swi_directive_expansion'(use_module(File), Expansion).

'$lgt_swi_directive_expansion'(module(Module,Exports0), [(:- module(Module,Exports))| Clauses]) :-
	'$lgt_swi_split_predicate_aliases'(Exports0, Exports, Clauses).

'$lgt_swi_directive_expansion'(reexport([]), []) :-
	!.
'$lgt_swi_directive_expansion'(reexport([File| Files]), [(:- use_module(Module, Exports)), (:- export(Exports))| Terms]) :-
	!,
	'$lgt_swi_list_of_exports'(File, Module, Exports0),
	'$lgt_swi_fix_predicate_aliases'(Exports0, Exports),
	'$lgt_swi_directive_expansion'(reexport(Files), Terms).
'$lgt_swi_directive_expansion'(reexport(File), [(:- use_module(Module, Exports)), (:- export(Exports))]) :-
	'$lgt_swi_list_of_exports'(File, Module, Exports0),
	'$lgt_swi_fix_predicate_aliases'(Exports0, Exports).

'$lgt_swi_directive_expansion'(reexport(File, Exports0), (:- reexport(Module, Exports))) :-
	'$lgt_swi_list_of_exports'(File, Module, OriginalExports),
	'$lgt_swi_filter_imports'(Exports0, OriginalExports, Exports1),
	'$lgt_swi_fix_predicate_aliases'(Exports1, Exports).

'$lgt_swi_directive_expansion'(thread_local(Predicates), [{:- thread_local(TPredicates)}, (:- dynamic(Predicates))]) :-
	logtalk_load_context(entity_type, module),
	'$lgt_compile_predicate_indicators'(Predicates, _, TPredicates).

'$lgt_swi_directive_expansion'(table(as(Predicates,Properties)), {:- table(as(TPredicates,Properties))}) :-
	logtalk_load_context(entity_type, _),
	'$lgt_swi_table_directive_expansion'(Predicates, TPredicates).

'$lgt_swi_directive_expansion'(table(Predicates), {:- table(TPredicates)}) :-
	logtalk_load_context(entity_type, _),
	'$lgt_swi_table_directive_expansion'(Predicates, TPredicates).

'$lgt_swi_directive_expansion'(dynamic(as(Predicates,Properties)), Expansion) :-
	'$lgt_swi_directive_expansion'(dynamic(Predicates,Properties), Expansion).

'$lgt_swi_directive_expansion'(dynamic(Predicates,Properties), [{:- dynamic(TPredicates,Properties)}, (:- dynamic(Predicates))| Directives]) :-
	logtalk_load_context(entity_type, _),
	'$lgt_compile_predicate_indicators'(Predicates, _, TPredicates),
	'$lgt_swi_dynamic_directive_expansion'(Properties, Predicates, TPredicates, Directives).

'$lgt_swi_directive_expansion'(begin_tests(_, _), (:- if(fail))) :-
	logtalk_load_context(entity_type, module).
'$lgt_swi_directive_expansion'(begin_tests(_), (:- if(fail))) :-
	logtalk_load_context(entity_type, module).
'$lgt_swi_directive_expansion'(end_tests(_), (:- endif)) :-
	logtalk_load_context(entity_type, module).

'$lgt_swi_table_directive_expansion'([Predicate| Predicates], [TPredicate| TPredicates]) :-
	!,
	'$lgt_swi_table_directive_predicate'(Predicate, TPredicate),
	'$lgt_swi_table_directive_expansion'(Predicates, TPredicates).

'$lgt_swi_table_directive_expansion'((Predicate, Predicates), (TPredicate, TPredicates)) :-
	!,
	'$lgt_swi_table_directive_predicate'(Predicate, TPredicate),
	'$lgt_swi_table_directive_expansion'(Predicates, TPredicates).

'$lgt_swi_table_directive_expansion'(Predicate, TPredicate) :-
	'$lgt_swi_table_directive_predicate'(Predicate, TPredicate).


'$lgt_swi_table_directive_predicate'(F/A, TF/TA) :-
	!,
	'$lgt_compile_predicate_indicators'(F/A, _, TF/TA).
'$lgt_swi_table_directive_predicate'(F//A, TF/TA) :-
	!,
	A2 is A + 2,
	'$lgt_compile_predicate_indicators'(F/A2, _, TF/TA).
'$lgt_swi_table_directive_predicate'(Head, THead) :-
	'$lgt_compile_predicate_heads'(Head, _, THead, _).


'$lgt_swi_dynamic_directive_expansion'([], _, _, []).
'$lgt_swi_dynamic_directive_expansion'([thread(Local)| Properties], Predicates, TPredicates, [{:- thread_local(TPredicates)}| Directives]) :-
	Local == local,
	!,
	'$lgt_swi_dynamic_directive_expansion'(Properties, Predicates, TPredicates, Directives).
'$lgt_swi_dynamic_directive_expansion'([multifile(Boolean)| Properties], Predicates, TPredicates, [(:- multifile(Predicates))| Directives]) :-
	Boolean == true,
	!,
	'$lgt_swi_dynamic_directive_expansion'(Properties, Predicates, TPredicates, Directives).
'$lgt_swi_dynamic_directive_expansion'([discontiguous(Boolean)| Properties], Predicates, TPredicates, [(:- discontiguous(Predicates))| Directives]) :-
	Boolean == true,
	!,
	'$lgt_swi_dynamic_directive_expansion'(Properties, Predicates, TPredicates, Directives).
'$lgt_swi_dynamic_directive_expansion'([volatile(Boolean)| Properties], Predicates, TPredicates, [{:- volatile(TPredicates)}| Directives]) :-
	Boolean == true,
	!,
	'$lgt_swi_dynamic_directive_expansion'(Properties, Predicates, TPredicates, Directives).
'$lgt_swi_dynamic_directive_expansion'([_| Properties], Predicates, TPredicates, Directives) :-
	!,
	'$lgt_swi_dynamic_directive_expansion'(Properties, Predicates, TPredicates, Directives).
'$lgt_swi_dynamic_directive_expansion'(Properties, Predicates, TPredicates, Directives) :-
	'$lgt_swi_conjunction_to_list'(Properties, List),
	'$lgt_swi_dynamic_directive_expansion'(List, Predicates, TPredicates, Directives).


'$lgt_swi_conjunction_to_list'(Term, [Term]) :-
	var(Term),
	!.
'$lgt_swi_conjunction_to_list'((Term, Conjunction), [Term| Terms]) :-
	!,
	'$lgt_swi_conjunction_to_list'(Conjunction, Terms).
'$lgt_swi_conjunction_to_list'(Term, [Term]).


'$lgt_swi_unify_head_thead_args'([], [_]).
'$lgt_swi_unify_head_thead_args'([Arg| Args], [Arg| ExtArgs]) :-
	'$lgt_swi_unify_head_thead_args'(Args, ExtArgs).


'$lgt_swi_list_of_exports'(File, Module, Exports) :-
	(	logtalk_load_context(directory, Directory)
	;	logtalk_load_context(file, IncludeFile),
		file_directory_name(IncludeFile, Directory)
	),
	absolute_file_name(File, Path, [file_type(prolog), access(read), file_errors(fail), relative_to(Directory)]),
	(	module_property(Module, file(Path)),
		% only succeeds for loaded modules
		module_property(Module, exports(Predicates)) ->
		(	module_property(Module, exported_operators(Operators)) ->
			% this property fails instead of returning the empty list!
			'$lgt_append'(Predicates, Operators, Exports)
		;	Exports = Predicates
		)
	;	object_property(Module, file(Path)),
		object_property(Module, module),
		% module compiled as an object
		object_property(Module, public(Exports))
	),
	!.
'$lgt_swi_list_of_exports'(File, Module, Exports) :-
	(	logtalk_load_context(directory, Directory)
	;	logtalk_load_context(file, IncludeFile),
		file_directory_name(IncludeFile, Directory)
	),
	(	absolute_file_name(File, Path, [file_type(prolog), access(read), file_errors(fail), relative_to(Directory)])
	;	% we may be compiling Prolog module files as Logtalk objects
		absolute_file_name(File, Path, [extensions(['.lgt','.logtalk']), access(read), file_errors(fail), relative_to(Directory)])
	),
	open(Path, read, In),
	% deal with #! script; if not present assume that the
	% module declaration is the first directive on the file
	(	peek_char(In, #) ->
		skip(In, 10)
	;	true
	),
	setup_call_cleanup(true, '$lgt_swi_read_module_directive'(In, Module, Exports), close(In)),
	(	var(Module) ->
		file_base_name(Path, Base),
		file_name_extension(Module, _, Base)
	;	true
	),
	!.

'$lgt_swi_read_module_directive'(Stream, Module, Exports) :-
	% fragile hack as it ignores predicates exported via reexport/1-2 directives
	read(Stream, FirstTerm),
	(	FirstTerm  = (:- module(Module, Exports)) ->
		true
	;	FirstTerm = (:- encoding(_)) ->
		read(Stream, SecondTerm),
		SecondTerm = (:- module(Module, Exports))
	;	fail
	).


'$lgt_swi_filter_imports'([], _, []).
'$lgt_swi_filter_imports'([Import| Imports], _, [Import| Imports]).
'$lgt_swi_filter_imports'(except(Excluded), Exports, Imports) :-
	findall(
		Import,
		(	'$lgt_member'(Import, Exports),
			\+ '$lgt_member'(Import, Excluded)
		),
		Imports
	).


'$lgt_swi_split_predicate_aliases'([], [], []).
'$lgt_swi_split_predicate_aliases'([as(Functor/Arity, Alias)| Exports0], [Alias/Arity| Exports], [Clause| Clauses]) :-
	!,
	functor(Template, Functor, Arity),
	Template =.. [Functor| Arguments],
	AliasTemplate =.. [Alias| Arguments],
	Clause = (AliasTemplate :- Template),
	'$lgt_swi_split_predicate_aliases'(Exports0, Exports, Clauses).
'$lgt_swi_split_predicate_aliases'([Export| Exports0], [Export| Exports], Clauses) :-
	'$lgt_swi_split_predicate_aliases'(Exports0, Exports, Clauses).


'$lgt_swi_fix_predicate_aliases'([], []).
'$lgt_swi_fix_predicate_aliases'([Import0| Imports0], [Import| Imports]) :-
	'$lgt_swi_fix_predicate_aliases_aux'([Import0| Imports0], [Import| Imports]).
'$lgt_swi_fix_predicate_aliases'(except(Excluded), except(Excluded)).

'$lgt_swi_fix_predicate_aliases_aux'([], []).
'$lgt_swi_fix_predicate_aliases_aux'([as(Functor/Arity,Alias)| Imports0], [as(Functor/Arity,Alias/Arity)| Imports]) :-
	atom(Alias),
	!,
	'$lgt_swi_fix_predicate_aliases_aux'(Imports0, Imports).
'$lgt_swi_fix_predicate_aliases_aux'([Import| Imports0], [Import| Imports]) :-
	'$lgt_swi_fix_predicate_aliases_aux'(Imports0, Imports).


'$lgt_swi_encoding_to_logtalk_encoding'(ascii, 'US-ASCII').
'$lgt_swi_encoding_to_logtalk_encoding'(iso_latin_1, 'ISO-8859-1').
'$lgt_swi_encoding_to_logtalk_encoding'(utf8, 'UTF-8').
'$lgt_swi_encoding_to_logtalk_encoding'(unicode_be, 'UCS-2BE').
'$lgt_swi_encoding_to_logtalk_encoding'(unicode_le, 'UCS-2LE').


% '$lgt_prolog_goal_expansion'(@callable, -callable)

'$lgt_prolog_goal_expansion'(table(Predicates), {table(TPredicates)}) :-
	predicate_property(table(_), built_in),
	logtalk_load_context(entity_type, _),
	'$lgt_swi_table_directive_expansion'(Predicates, TPredicates).

'$lgt_prolog_goal_expansion'(untable(Predicates), {untable(TPredicates)}) :-
	predicate_property(untable(_), built_in),
	logtalk_load_context(entity_type, _),
	'$lgt_swi_table_directive_expansion'(Predicates, TPredicates).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  multi-threading predicates
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% thread_property(+atom, ?nonvar) -- built-in


% thread_self(?atom) -- built-in


% thread_create(@callable, -thread_id, +list) -- built-in


% thread_join(+atom, -nonvar) -- built-in


% thread_detach(+atom) -- built-in


% thread_exit(@term) -- built-in


% thread_send_message(+atom, @callable) -- built-in


% thread_peek_message(+atom, ?callable) -- built-in


% thread_get_message(+atom, ?callable) -- built-in


% thread_get_message(?callable) -- built-in


% thread_sleep(+number)

thread_sleep(Time) :-
	sleep(Time).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  converts between Prolog stream encoding names and XML encoding names
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_logtalk_prolog_encoding'(?atom, ?atom, +stream)

'$lgt_logtalk_prolog_encoding'('US-ASCII', ascii, _).
'$lgt_logtalk_prolog_encoding'('ISO-8859-1', iso_latin_1, _).
'$lgt_logtalk_prolog_encoding'('UTF-8', utf8, _).
'$lgt_logtalk_prolog_encoding'('UCS-2', Encoding, Stream) :-	% BOM mandatory
	(	stream_property(Stream, encoding(unicode_be)) ->
		Encoding = unicode_be
	;	stream_property(Stream, encoding(unicode_le)) ->
		Encoding = unicode_le
	;	stream_property(Stream, encoding(utf16le)) ->
		Encoding = utf16le
	;	stream_property(Stream, encoding(utf16be)) ->
		Encoding = utf16be
	).
'$lgt_logtalk_prolog_encoding'('UCS-2BE', unicode_be, _).		% BOM forbidden
'$lgt_logtalk_prolog_encoding'('UCS-2LE', unicode_le, _).
'$lgt_logtalk_prolog_encoding'('UTF-16', Encoding, Stream) :-	% BOM optional but strongly recommended
	(	stream_property(Stream, encoding(unicode_be)) ->		% not true of course but usually we can get away with it
		Encoding = unicode_be
	;	stream_property(Stream, encoding(unicode_le)) ->
		Encoding = unicode_le
	;	stream_property(Stream, encoding(utf16le)) ->
		Encoding = utf16le
	;	stream_property(Stream, encoding(utf16be)) ->
		Encoding = utf16be
	).
'$lgt_logtalk_prolog_encoding'('UTF-16BE', unicode_be, _).		% BOM forbidden
'$lgt_logtalk_prolog_encoding'('UTF-16LE', unicode_le, _).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  lambda expressions support predicates
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_copy_term_without_constraints'(@term, ?term)

'$lgt_copy_term_without_constraints'(Term, Copy) :-
	copy_term_nat(Term, Copy).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  goal_expansion/2 rules to allow calling the Prolog built-in predicates
%  phrase/2-3 with a Object::GRBody as the first argument and to optimize
%  ::/2 goals from within modules
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


:- dynamic(user:goal_expansion/2).
:- multifile(user:goal_expansion/2).

% optimize portable format/2-3 calls
user:goal_expansion('$lgt_format'(Stream, Format, Arguments), format(Stream, Format, Arguments)).
user:goal_expansion('$lgt_format'(Format, Arguments), format(Format, Arguments)).

% support calls to phrase/2 that call object non-terminals
user:goal_expansion(phrase(Rule, Input, Rest), ExpandedGoal) :-
	nonvar(Rule),
	functor(Rule, '::', 2),
	!,
	'$lgt_execution_context'(ExCtx, user, user, user, user, [], []),
	'$lgt_user_module_qualification'('$lgt_phrase'(Rule, Input, Rest, ExCtx), ExpandedGoal).
% support calls to phrase/3 that call object non-terminals
user:goal_expansion(phrase(Rule, Input), ExpandedGoal) :-
	nonvar(Rule),
	functor(Rule, '::', 2),
	!,
	'$lgt_execution_context'(ExCtx, user, user, user, user, [], []),
	'$lgt_user_module_qualification'('$lgt_phrase'(Rule, Input, ExCtx), ExpandedGoal).
% optimize messages sent from modules (including "user")
user:goal_expansion('::'(Object, Message), ExpandedGoal) :-
	callable(Object),
	callable(Message),
	% check that the object is not compiled in debug mode
	'$lgt_current_object_'(Object, _, _, _, _, _, _, _, _, _, Flags),
	Flags /\ 512 =\= 512,
	% find out in which module Logtalk was loaded (usually, "user")
	'$lgt_user_module_qualification'(xx, QualifiedGoal),
	QualifiedGoal = ':'(UserModule, xx),
	% this module plays the role of the Logtalk pseudo-object "user"
	(	prolog_load_context(term_position, Position),
		stream_position_data(line_count, Position, Line) ->
		% loading a file
		prolog_load_context(module, Module),
		Module \== UserModule,
		% loading a Prolog module file
		'$lgt_compiler_flag'(events, Events)
	;	% top-level goal
		Line = -1,
		% use default value of the "events" flag
		'$lgt_current_flag_'(events, Events)
	),
	'$lgt_comp_ctx'(Ctx, _, _, user, user, user, Obj, _, [], [], ExCtx, compile(aux,_,_), [], Line-Line, _),
	'$lgt_execution_context'(ExCtx, user, user, user, Obj, [], []),
	catch('$lgt_compile_message_to_object'(Message, Object, Goal, Events, Ctx), _, fail),
	'$lgt_user_module_qualification'(Goal, ExpandedGoal).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  hooks predicates for writing and asserting compiled entity terms
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_write_compiled_term'(@stream, @callable, +atom, +atom, +integer)
%
% the third argument is the term type: runtime (internal runtime clause),
% user (compiled user-defined term), or aux (auxiliary clause resulting
% e.g. from term-expansion)

'$lgt_write_compiled_term'(Stream, Term, _, _, _) :-
	current_prolog_flag(logtalk_source_location_data, false),
	!,
	write_canonical(Stream, Term), write(Stream, '.\n').

'$lgt_write_compiled_term'(Stream, '$lgt_current_object_'(Obj,Prefix,Dcl,Def,Super,IDcl,IDef,DDcl,DDef,Rnm,Flags), _, _, _) :-
	!,
	write_canonical(Stream, (:- '$hide'(Dcl/4))),   write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Dcl/6))),   write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Def/3))),   write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Def/5))),   write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Super/5))), write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(IDcl/6))),  write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(IDef/5))),  write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(DDcl/2))),  write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(DDef/3))),  write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Rnm/3))),   write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Dcl/4))),   write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Dcl/6))),   write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Def/3))),   write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Def/5))),   write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Super/5))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(IDcl/6))),  write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(IDef/5))),  write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(DDcl/2))),  write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(DDef/3))),  write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Rnm/3))),   write(Stream, '.\n'),
	write_canonical(Stream, '$lgt_current_object_'(Obj,Prefix,Dcl,Def,Super,IDcl,IDef,DDcl,DDef,Rnm,Flags)),
	write(Stream, '.\n').

'$lgt_write_compiled_term'(Stream, '$lgt_current_category_'(Ctg,Prefix,Dcl,Def,Rnm,Flags), _, _, _) :-
	!,
	write_canonical(Stream, (:- '$hide'(Dcl/4))), write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Dcl/5))), write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Def/3))), write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Def/4))), write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Rnm/3))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Dcl/4))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Dcl/5))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Def/3))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Def/4))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Rnm/3))), write(Stream, '.\n'),
	write_canonical(Stream, '$lgt_current_category_'(Ctg,Prefix,Dcl,Def,Rnm,Flags)),
	write(Stream, '.\n').

'$lgt_write_compiled_term'(Stream, '$lgt_current_protocol_'(Ptc,Prefix,Dcl,Rnm,Flags), _, _, _) :-
	!,
	write_canonical(Stream, (:- '$hide'(Dcl/4))), write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Dcl/5))), write(Stream, '.\n'),
	write_canonical(Stream, (:- '$hide'(Rnm/3))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Dcl/4))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Dcl/5))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Rnm/3))), write(Stream, '.\n'),
	write_canonical(Stream, '$lgt_current_protocol_'(Ptc,Prefix,Dcl,Rnm,Flags)),
	write(Stream, '.\n').

'$lgt_write_compiled_term'(Stream, Term, runtime, _, _) :-
	!,
	write_canonical(Stream, Term), write(Stream, '.\n').

'$lgt_write_compiled_term'(Stream, (:- Directive), _, _, _) :-
	% to cope with {(:- Directive)} entity terms
	!,
	write_canonical(Stream, (:- Directive)), write(Stream, '.\n').

'$lgt_write_compiled_term'(Stream, Term, user, File, Line) :-
	!,
	write_canonical(Stream, '$source_location'(File,Line):Term), write(Stream, '.\n').

'$lgt_write_compiled_term'(Stream, Term, aux, _, _) :-
	!,
	(	Term = (Head :- _) ->
		true
	;	Term = Head
	),
	functor(Head, Functor, Arity),
	write_canonical(Stream, (:- '$hide'(Functor/Arity))), write(Stream, '.\n'),
	write_canonical(Stream, (:- noprofile(Functor/Arity))), write(Stream, '.\n'),
	write_canonical(Stream, Term), write(Stream, '.\n').

'$lgt_write_compiled_term'(Stream, Term, _, File, Line) :-
	write_canonical(Stream, '$source_location'(File,Line):Term), write(Stream, '.\n').


% '$lgt_assertz_entity_clause'(@clause, +atom)

'$lgt_assertz_entity_clause'('$lgt_current_object_'(Obj,Prefix,Dcl,Def,Super,IDcl,IDef,DDcl,DDef,Rnm,Flags), _) :-
	!,
	'$hide'(Dcl/4),
	'$hide'(Dcl/6),
	'$hide'(Def/3),
	'$hide'(Def/5),
	'$hide'(Super/5),
	'$hide'(IDcl/6),
	'$hide'(IDef/5),
	'$hide'(DDcl/2),
	'$hide'(DDef/3),
	'$hide'(Rnm/3),
	noprofile(Dcl/4),
	noprofile(Dcl/6),
	noprofile(Def/3),
	noprofile(Def/5),
	noprofile(Super/5),
	noprofile(IDcl/6),
	noprofile(IDef/5),
	noprofile(DDcl/2),
	noprofile(DDef/3),
	noprofile(Rnm/3),
	assertz('$lgt_current_object_'(Obj,Prefix,Dcl,Def,Super,IDcl,IDef,DDcl,DDef,Rnm,Flags)).

'$lgt_assertz_entity_clause'('$lgt_current_category_'(Ctg,Prefix,Dcl,Def,Rnm,Flags), _) :-
	!,
	'$hide'(Dcl/4),
	'$hide'(Dcl/5),
	'$hide'(Def/3),
	'$hide'(Def/4),
	'$hide'(Rnm/3),
	noprofile(Dcl/4),
	noprofile(Dcl/5),
	noprofile(Def/3),
	noprofile(Def/4),
	noprofile(Rnm/3),
	assertz('$lgt_current_category_'(Ctg,Prefix,Dcl,Def,Rnm,Flags)).

'$lgt_assertz_entity_clause'('$lgt_current_protocol_'(Ptc,Prefix,Dcl,Rnm,Flags), _) :-
	!,
	'$hide'(Dcl/4),
	'$hide'(Dcl/5),
	'$hide'(Rnm/3),
	noprofile(Dcl/4),
	noprofile(Dcl/5),
	noprofile(Rnm/3),
	assertz('$lgt_current_protocol_'(Ptc,Prefix,Dcl,Rnm,Flags)).

'$lgt_assertz_entity_clause'(Term, aux) :-
	!,
	(	Term = (Head :- _) ->
		true
	;	Term = Head
	),
	functor(Head, Functor, Arity),
	'$hide'(Functor/Arity),
	noprofile(Functor/Arity),
	assertz(Term).

'$lgt_assertz_entity_clause'(Term, _) :-
	assertz(Term).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  error term normalization (when exception terms don't follow the ISO
%  Prolog standard)
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_normalize_error_term'(@callable, -callable)

'$lgt_normalize_error_term'(Error, NormalizedError) :-
	(	nonvar(Error),
		Error = error(ErrorTerm, Context),
		nonvar(Context),
		Context = context(TFunctor/TArity, _),
		'$lgt_decompile_predicate_indicators'(TFunctor/TArity, Entity, _, Functor/Arity),
		functor(Goal, Functor, Arity) ->
		NormalizedError = error(ErrorTerm, logtalk(Goal, Entity))
	;	NormalizedError = Error
	).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  message token printing
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


:- multifile('$logtalk#0.print_message_token#4'/5).
:- dynamic('$logtalk#0.print_message_token#4'/5).

'$logtalk#0.print_message_token#4'(Stream, _, ansi(Attributes, Format, Arguments), _, _) :-
	prolog:message_line_element(Stream, ansi(Attributes, Format, Arguments)).

'$logtalk#0.print_message_token#4'(Stream, _, begin(Kind0, Var), _, _) :-
	'$lgt_swi_convert_message_kind'(Kind0, Kind),
	prolog:message_line_element(Stream, begin(Kind, Var)).

'$logtalk#0.print_message_token#4'(Stream, _, end(Var), _, _) :-
	prolog:message_line_element(Stream, end(Var)).


'$lgt_swi_convert_message_kind'(comment, informational) :- !.
'$lgt_swi_convert_message_kind'(comment(_), informational) :- !.
'$lgt_swi_convert_message_kind'(Kind0, Kind) :-
	functor(Kind0, Kind, _).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  term hashing (not currently used in the compiler/runtime)
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% term_hash(@callable, +integer, +integer, -integer) -- built-in



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  atomics concat (not currently used in the compiler/runtime)
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% atomic_concat(+atomic, +atomic, ?atom) -- built-in


% atomic_list_concat(@list(atomic), ?atom) -- built-in


% atomic_list_concat(@list(atomic), +atom, ?atom) -- built-in



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  string built-in type
%
%  define these predicates to trivially fail if no string type is available
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_string'(@term)

'$lgt_string'(String) :-
	string(String).


% '$lgt_string_codes'(+string, -list(codes))
% '$lgt_string_codes'(-string, +list(codes))

'$lgt_string_codes'(String, Codes) :-
	string_codes(String, Codes).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  module qualification to be used when calling Prolog meta-predicates
%  with meta-arguments that are calls to object or category predicates
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_user_module_qualification'(@callable, -callable)

term_expansion(
		'$lgt_user_module_qualification'(_, _),
		'$lgt_user_module_qualification'(Goal, Module:Goal)) :-
	prolog_load_context(module, Module).

'$lgt_user_module_qualification'(_, _).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  auxiliary predicates for compiling modules as objects
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% '$lgt_find_module_predicate'(+atom, -atom, @callable)
%
% succeeds when Module:Predicate is visible in module Current

'$lgt_find_visible_module_predicate'(_Current, Module, Predicate) :-
	predicate_property(Predicate, imported_from(Module)).
'$lgt_find_visible_module_predicate'(Current, Module, Predicate) :-
	import_module(Current, Module),
	predicate_property(Predicate, defined),
	!.


% '$lgt_current_module_predicate'(+atom, +predicate_indicator)
%
% succeeds when Module defines Predicate

'$lgt_current_module_predicate'(Module, Predicate) :-
	current_predicate(Module:Predicate).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  shortcuts to the Logtalk built-in predicates logtalk_load/1 and
%  logtalk_make/1
%
%  defined in the adapter files to make it easier to comment them out in case
%  of conflict with some Prolog native feature; they require conformance with
%  the ISO Prolog standard regarding the definition of the {}/1 syntax
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


{X} :-
	var(X),
	throw(error(instantiation_error, logtalk({X}, _))).
{*} :-
	!,
	logtalk_make(all).
{!} :-
	!,
	logtalk_make(clean).
{?} :-
	!,
	logtalk_make(check).
{@} :-
	!,
	logtalk_make(circular).
{#} :-
	!,
	logtalk_make(documentation).
{+d} :-
	!,
	logtalk_make(debug).
{+n} :-
	!,
	logtalk_make(normal).
{+o} :-
	!,
	logtalk_make(optimal).
{+f} :-
	!,
	logtalk_make(force).
{$} :-
	!,
	logtalk_make(caches).

{Files} :-
	'$lgt_conjunction_to_list'(Files, List),
	logtalk_load(List).



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  end!
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
