/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (c) 1985-2017, University of Amsterdam VU University Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ :- module('$toplevel', [ '$initialise'/0, % start Prolog '$toplevel'/0, % Prolog top-level (re-entrant) '$compile'/0, % `-c' toplevel initialize/0, % Run program initialization version/0, % Write initial banner version/1, % Add message to the banner prolog/0, % user toplevel predicate '$query_loop'/0, % toplevel predicate residual_goals/1, % +Callable (initialization)/1, % initialization goal (directive) '$thread_init'/0, % initialise thread (thread_initialization)/1 % thread initialization goal ]). /******************************* * FILE_SEARCH_PATH * *******************************/ :- multifile user:file_search_path/2. user:file_search_path(user_profile, app_preferences('.')). :- if(current_prolog_flag(windows, true)). user:file_search_path(app_preferences, app_data('.')). user:file_search_path(app_data, PrologAppData) :- current_prolog_flag(windows, true), catch(win_folder(appdata, AppData), _, fail), atom_concat(AppData, '/SWI-Prolog', PrologAppData), ( exists_directory(PrologAppData) -> true ; catch(make_directory(PrologAppData), _, fail) ). :- else. user:file_search_path(app_data, UserLibDir) :- catch(expand_file_name('~/lib/swipl', [UserLibDir]), _, fail). :- endif. user:file_search_path(app_preferences, UserHome) :- catch(expand_file_name(~, [UserHome]), _, fail). /******************************* * VERSION BANNER * *******************************/ :- dynamic prolog:version_msg/1. %! version is det. % % Print the Prolog banner message and messages registered using % version/1. version :- print_message(banner, welcome). %! version(+Message) is det. % % Add message to version/0 :- multifile system:term_expansion/2. system:term_expansion((:- version(Message)), prolog:version_msg(Message)). version(Message) :- ( prolog:version_msg(Message) -> true ; assertz(prolog:version_msg(Message)) ). /******************************** * INITIALISATION * *********************************/ % note: loaded_init_file/2 is used by prolog_load_context/2 to % confirm we are loading a script. :- dynamic loaded_init_file/2. % already loaded init files '$load_init_file'(none) :- !. '$load_init_file'(Base) :- loaded_init_file(Base, _), !. '$load_init_file'(InitFile) :- exists_file(InitFile), !, ensure_loaded(user:InitFile). '$load_init_file'(Base) :- absolute_file_name(user_profile(Base), InitFile, [ access(read), file_errors(fail) ]), asserta(loaded_init_file(Base, InitFile)), load_files(user:InitFile, [ scope_settings(false) ]). '$load_init_file'(_). '$load_system_init_file' :- loaded_init_file(system, _), !. '$load_system_init_file' :- '$cmd_option_val'(system_init_file, Base), Base \== none, current_prolog_flag(home, Home), file_name_extension(Base, rc, Name), atomic_list_concat([Home, '/', Name], File), absolute_file_name(File, Path, [ file_type(prolog), access(read), file_errors(fail) ]), asserta(loaded_init_file(system, Path)), load_files(user:Path, [ silent(true), scope_settings(false) ]), !. '$load_system_init_file'. '$load_script_file' :- loaded_init_file(script, _), !. '$load_script_file' :- '$cmd_option_val'(script_file, OsFiles), load_script_files(OsFiles). load_script_files([]). load_script_files([OsFile|More]) :- prolog_to_os_filename(File, OsFile), ( absolute_file_name(File, Path, [ file_type(prolog), access(read), file_errors(fail) ]) -> asserta(loaded_init_file(script, Path)), load_files(user:Path, []), load_files(More) ; throw(error(existence_error(script_file, File), _)) ). /******************************* * AT_INITIALISATION * *******************************/ :- meta_predicate initialization(0). :- '$iso'((initialization)/1). %! initialization(:Goal) % % Runs Goal after loading the file in which this directive % appears as well as after restoring a saved state. % % @see initialization/2 initialization(Goal) :- Goal = _:G, prolog:initialize_now(G, Use), !, print_message(warning, initialize_now(G, Use)), initialization(Goal, now). initialization(Goal) :- initialization(Goal, after_load). :- multifile prolog:initialize_now/2, prolog:message//1. prolog:initialize_now(load_foreign_library(_), 'use :- use_foreign_library/1 instead'). prolog:initialize_now(load_foreign_library(_,_), 'use :- use_foreign_library/2 instead'). prolog:message(initialize_now(Goal, Use)) --> [ 'Initialization goal ~p will be executed'-[Goal],nl, 'immediately for backward compatibility reasons', nl, '~w'-[Use] ]. '$run_initialization' :- '$run_initialization'(_, []), '$thread_init'. %! initialize % % Run goals registered with `:- initialization(Goal, program).`. Stop % with an exception if a goal fails or raises an exception. initialize :- forall('$init_goal'(when(program), Goal, Ctx), run_initialize(Goal, Ctx)). run_initialize(Goal, Ctx) :- ( catch(Goal, E, true), ( var(E) -> true ; throw(error(initialization_error(E, Goal, Ctx), _)) ) ; throw(error(initialization_error(failed, Goal, Ctx), _)) ). /******************************* * THREAD INITIALIZATION * *******************************/ :- meta_predicate thread_initialization(0). :- dynamic '$at_thread_initialization'/1. %! thread_initialization(:Goal) % % Run Goal now and everytime a new thread is created. thread_initialization(Goal) :- assert('$at_thread_initialization'(Goal)), call(Goal), !. '$thread_init' :- ( '$at_thread_initialization'(Goal), ( call(Goal) -> fail ; fail ) ; true ). /******************************* * FILE SEARCH PATH (-p) * *******************************/ %! '$set_file_search_paths' is det. % % Process -p PathSpec options. '$set_file_search_paths' :- '$cmd_option_val'(search_paths, Paths), ( '$member'(Path, Paths), atom_chars(Path, Chars), ( phrase('$search_path'(Name, Aliases), Chars) -> '$reverse'(Aliases, Aliases1), forall('$member'(Alias, Aliases1), asserta(user:file_search_path(Name, Alias))) ; print_message(error, commandline_arg_type(p, Path)) ), fail ; true ). '$search_path'(Name, Aliases) --> '$string'(NameChars), [=], !, {atom_chars(Name, NameChars)}, '$search_aliases'(Aliases). '$search_aliases'([Alias|More]) --> '$string'(AliasChars), path_sep, !, { '$make_alias'(AliasChars, Alias) }, '$search_aliases'(More). '$search_aliases'([Alias]) --> '$string'(AliasChars), '$eos', !, { '$make_alias'(AliasChars, Alias) }. path_sep --> { current_prolog_flag(windows, true) }, !, [;]. path_sep --> [:]. '$string'([]) --> []. '$string'([H|T]) --> [H], '$string'(T). '$eos'([], []). '$make_alias'(Chars, Alias) :- catch(term_to_atom(Alias, Chars), _, fail), ( atom(Alias) ; functor(Alias, F, 1), F \== / ), !. '$make_alias'(Chars, Alias) :- atom_chars(Alias, Chars). /******************************* * LOADING ASSIOCIATED FILES * *******************************/ %! argv_files(-Files) is det. % % Update the Prolog flag =argv=, extracting the leading directory and % files. argv_files(Files) :- current_prolog_flag(argv, Argv), no_option_files(Argv, Argv1, Files), ( Argv1 \== Argv -> set_prolog_flag(argv, Argv1) ; true ). no_option_files([--|Argv], Argv, []) :- !. no_option_files([OsScript|Argv], Argv, [Script]) :- prolog_to_os_filename(Script, OsScript), access_file(Script, read), catch(setup_call_cleanup( open(Script, read, In), ( get_char(In, '#'), get_char(In, '!') ), close(In)), _, fail), !. no_option_files([OsFile|Argv0], Argv, [File|T]) :- file_name_extension(_, Ext, OsFile), user:prolog_file_type(Ext, prolog), !, prolog_to_os_filename(File, OsFile), no_option_files(Argv0, Argv, T). no_option_files(Argv, Argv, []). clean_argv :- ( current_prolog_flag(argv, [--|Argv]) -> set_prolog_flag(argv, Argv) ; true ). %! associated_files(-Files) % % If SWI-Prolog is started as ., where is % the extension registered for associated files, set the Prolog % flag associated_file, switch to the directory holding the file % and -if possible- adjust the window title. associated_files([]) :- current_prolog_flag(saved_program_class, runtime), !, clean_argv. associated_files(Files) :- '$set_prolog_file_extension', argv_files(Files), ( Files = [File|_] -> absolute_file_name(File, AbsFile), set_prolog_flag(associated_file, AbsFile), set_working_directory(File), set_window_title(Files) ; true ). %! set_working_directory(+File) % % When opening as a GUI application, e.g., by opening a file from % the Finder/Explorer/..., we typically want to change working % directory to the location of the primary file. We currently % detect that we are a GUI app by the Prolog flag =console_menu=, % which is set by swipl-win[.exe]. set_working_directory(File) :- current_prolog_flag(console_menu, true), access_file(File, read), !, file_directory_name(File, Dir), working_directory(_, Dir). set_working_directory(_). set_window_title([File|More]) :- current_predicate(system:window_title/2), !, ( More == [] -> Extra = [] ; Extra = ['...'] ), atomic_list_concat(['SWI-Prolog --', File | Extra], ' ', Title), system:window_title(_, Title). set_window_title(_). %! start_pldoc % % If the option =|--pldoc[=port]|= is given, load the PlDoc % system. start_pldoc :- '$cmd_option_val'(pldoc_server, Server), ( Server == '' -> call((doc_server(_), doc_browser)) ; catch(atom_number(Server, Port), _, fail) -> call(doc_server(Port)) ; print_message(error, option_usage(pldoc)), halt(1) ). start_pldoc. %! load_associated_files(+Files) % % Load Prolog files specified from the commandline. load_associated_files(Files) :- ( '$member'(File, Files), load_files(user:File, [expand(false)]), fail ; true ). :- if(current_predicate(system:win_registry_get_value/3)). hkey('HKEY_CURRENT_USER/Software/SWI/Prolog'). hkey('HKEY_LOCAL_MACHINE/Software/SWI/Prolog'). '$set_prolog_file_extension' :- hkey(Key), catch(win_registry_get_value(Key, fileExtension, Ext0), _, fail), !, ( atom_concat('.', Ext, Ext0) -> true ; Ext = Ext0 ), ( user:prolog_file_type(Ext, prolog) -> true ; asserta(user:prolog_file_type(Ext, prolog)) ). :- endif. '$set_prolog_file_extension'. /******************************** * TOPLEVEL GOALS * *********************************/ %! '$initialise' is semidet. % % Called from PL_initialise() to do the Prolog part of the % initialization. If an exception occurs, this is printed and % '$initialise' fails. '$initialise' :- catch(initialise_prolog, E, initialise_error(E)). initialise_error('$aborted') :- !. initialise_error(E) :- print_message(error, initialization_exception(E)), fail. initialise_prolog :- '$clean_history', set_toplevel, associated_files(Files), '$set_file_search_paths', init_debug_flags, '$run_initialization', '$load_system_init_file', start_pldoc, attach_packs, '$cmd_option_val'(init_file, OsFile), prolog_to_os_filename(File, OsFile), '$load_init_file'(File), '$load_script_file', load_associated_files(Files), '$cmd_option_val'(goals, Goals), ( Goals == [], \+ '$init_goal'(when(_), _, _) -> version % default interactive run ; run_init_goals(Goals), ( load_only -> version ; run_program_init, run_main_init ) ). set_toplevel :- '$cmd_option_val'(toplevel, TopLevelAtom), catch(term_to_atom(TopLevel, TopLevelAtom), E, (print_message(error, E), halt(1))), create_prolog_flag(toplevel_goal, TopLevel, [type(term)]). load_only :- current_prolog_flag(os_argv, OSArgv), memberchk('-l', OSArgv), current_prolog_flag(argv, Argv), \+ memberchk('-l', Argv). %! run_init_goals(+Goals) is det. % % Run registered initialization goals on order. If a goal fails, % execution is halted. run_init_goals([]). run_init_goals([H|T]) :- run_init_goal(H), run_init_goals(T). run_init_goal(Text) :- catch(term_to_atom(Goal, Text), E, ( print_message(error, init_goal_syntax(E, Text)), halt(2) )), run_init_goal(Goal, Text). %! run_program_init is det. % % Run goals registered using run_program_init :- forall('$init_goal'(when(program), Goal, Ctx), run_init_goal(Goal, @(Goal,Ctx))). run_main_init :- findall(Goal-Ctx, '$init_goal'(when(main), Goal, Ctx), Pairs), '$last'(Pairs, Goal-Ctx), !, ( current_prolog_flag(toplevel_goal, default) -> set_prolog_flag(toplevel_goal, halt) ; true ), run_init_goal(Goal, @(Goal,Ctx)). run_main_init. run_init_goal(Goal, Ctx) :- ( catch(user:Goal, E, true) -> ( var(E) -> true ; print_message(error, init_goal_failed(E, Ctx)), halt(2) ) ; ( current_prolog_flag(verbose, silent) -> Level = silent ; Level = error ), print_message(Level, init_goal_failed(failed, Ctx)), halt(1) ). %! init_debug_flags is det. % % Initialize the various Prolog flags that control the debugger and % toplevel. init_debug_flags :- once(print_predicate(_, [print], PrintOptions)), create_prolog_flag(answer_write_options, PrintOptions, []), create_prolog_flag(prompt_alternatives_on, determinism, []), create_prolog_flag(toplevel_extra_white_line, true, []), create_prolog_flag(toplevel_print_factorized, false, []), create_prolog_flag(print_write_options, [ portray(true), quoted(true), numbervars(true) ], []), create_prolog_flag(toplevel_residue_vars, false, []), '$set_debugger_write_options'(print). %! setup_backtrace % % Initialise printing a backtrace. setup_backtrace :- ( \+ current_prolog_flag(backtrace, false), load_setup_file(library(prolog_stack)) -> true ; true ). %! setup_colors is det. % % Setup interactive usage by enabling colored output. setup_colors :- ( stream_property(user_input, tty(true)), stream_property(user_error, tty(true)), stream_property(user_output, tty(true)), \+ current_prolog_flag(color_term, false), load_setup_file(user:library(ansi_term)) -> true ; true ). %! setup_history % % Enable per-directory persistent history. setup_history :- ( \+ current_prolog_flag(save_history, false), stream_property(user_input, tty(true)), \+ current_prolog_flag(readline, false), load_setup_file(library(prolog_history)) -> prolog_history(enable) ; true ), set_default_history, '$load_history'. %! setup_readline % % Setup line editing. setup_readline :- ( current_prolog_flag(readline, swipl_win) -> true ; stream_property(user_input, tty(true)), current_prolog_flag(tty_control, true), \+ getenv('TERM', dumb), ( current_prolog_flag(readline, ReadLine) -> true ; ReadLine = true ), readline_library(ReadLine, Library), load_setup_file(library(Library)) -> set_prolog_flag(readline, Library) ; set_prolog_flag(readline, false) ). readline_library(true, Library) :- !, preferred_readline(Library). readline_library(false, _) :- !, fail. readline_library(Library, Library). preferred_readline(editline). preferred_readline(readline). %! load_setup_file(+File) is semidet. % % Load a file and fail silently if the file does not exist. load_setup_file(File) :- catch(load_files(File, [ silent(true), if(not_loaded) ]), _, fail). :- '$hide'('$toplevel'/0). % avoid in the GUI stacktrace %! '$toplevel' % % Called from PL_toplevel() '$toplevel' :- '$runtoplevel', print_message(informational, halt). %! '$runtoplevel' % % Actually run the toplevel. The values `default` and `prolog` both % start the interactive toplevel, where `prolog` implies the user gave % =|-t prolog|=. % % @see prolog/0 is the default interactive toplevel '$runtoplevel' :- current_prolog_flag(toplevel_goal, TopLevel0), toplevel_goal(TopLevel0, TopLevel), user:TopLevel. :- dynamic setup_done/0. :- volatile setup_done/0. toplevel_goal(default, '$query_loop') :- !, setup_interactive. toplevel_goal(prolog, '$query_loop') :- !, setup_interactive. toplevel_goal(Goal, Goal). setup_interactive :- setup_done, !. setup_interactive :- asserta(setup_done), catch(setup_backtrace, E, print_message(warning, E)), catch(setup_colors, E, print_message(warning, E)), catch(setup_readline, E, print_message(warning, E)), catch(setup_history, E, print_message(warning, E)). %! '$compile' % % Toplevel called when invoked with -c option. '$compile' :- '$set_file_search_paths', init_debug_flags, '$run_initialization', catch('$compile_wic', E, (print_message(error, E), halt(1))). /******************************** * USER INTERACTIVE LOOP * *********************************/ %! prolog % % Run the Prolog toplevel. This is now the same as break/0, which % pretends to be in a break-level if there is a parent % environment. prolog :- break. :- create_prolog_flag(toplevel_mode, backtracking, []). %! '$query_loop' % % Run the normal Prolog query loop. Note that the query is not % protected by catch/3. Dealing with unhandled exceptions is done % by the C-function query_loop(). This ensures that unhandled % exceptions are really unhandled (in Prolog). '$query_loop' :- current_prolog_flag(toplevel_mode, recursive), !, break_level(Level), read_expanded_query(Level, Query, Bindings), ( Query == end_of_file -> print_message(query, query(eof)) ; '$call_no_catch'('$execute'(Query, Bindings)), ( current_prolog_flag(toplevel_mode, recursive) -> '$query_loop' ; '$switch_toplevel_mode'(backtracking), '$query_loop' % Maybe throw('$switch_toplevel_mode')? ) ). '$query_loop' :- break_level(BreakLev), repeat, read_expanded_query(BreakLev, Query, Bindings), ( Query == end_of_file -> !, print_message(query, query(eof)) ; '$execute'(Query, Bindings), ( current_prolog_flag(toplevel_mode, recursive) -> !, '$switch_toplevel_mode'(recursive), '$query_loop' ; fail ) ). break_level(BreakLev) :- ( current_prolog_flag(break_level, BreakLev) -> true ; BreakLev = -1 ). read_expanded_query(BreakLev, ExpandedQuery, ExpandedBindings) :- '$current_typein_module'(TypeIn), ( stream_property(user_input, tty(true)) -> '$system_prompt'(TypeIn, BreakLev, Prompt), prompt(Old, '| ') ; Prompt = '', prompt(Old, '') ), trim_stacks, repeat, read_query(Prompt, Query, Bindings), prompt(_, Old), catch(call_expand_query(Query, ExpandedQuery, Bindings, ExpandedBindings), Error, (print_message(error, Error), fail)), !. %! read_query(+Prompt, -Goal, -Bindings) is det. % % Read the next query. The first clause deals with the case where % !-based history is enabled. The second is used if we have command % line editing. read_query(Prompt, Goal, Bindings) :- current_prolog_flag(history, N), integer(N), N > 0, !, read_history(h, '!h', [trace, end_of_file], Prompt, Goal, Bindings). read_query(Prompt, Goal, Bindings) :- remove_history_prompt(Prompt, Prompt1), repeat, % over syntax errors prompt1(Prompt1), read_query_line(user_input, Line), '$save_history_line'(Line), % save raw line (edit syntax errors) '$current_typein_module'(TypeIn), catch(read_term_from_atom(Line, Goal, [ variable_names(Bindings), module(TypeIn) ]), E, ( print_message(error, E), fail )), !, '$save_history_event'(Line). % save event (no syntax errors) %! read_query_line(+Input, -Line) is det. read_query_line(Input, Line) :- catch(read_term_as_atom(Input, Line), Error, true), save_debug_after_read, ( var(Error) -> true ; Error = error(syntax_error(_),_) -> print_message(error, Error), fail ; print_message(error, Error), throw(Error) ). %! read_term_as_atom(+Input, -Line) % % Read the next term as an atom and skip to the newline or a % non-space character. read_term_as_atom(In, Line) :- '$raw_read'(In, Line), ( Line == end_of_file -> true ; skip_to_nl(In) ). %! skip_to_nl(+Input) is det. % % Read input after the term. Skips white space and %... comment % until the end of the line or a non-blank character. skip_to_nl(In) :- repeat, peek_char(In, C), ( C == '%' -> skip(In, '\n') ; char_type(C, space) -> get_char(In, _), C == '\n' ; true ), !. remove_history_prompt('', '') :- !. remove_history_prompt(Prompt0, Prompt) :- atom_chars(Prompt0, Chars0), clean_history_prompt_chars(Chars0, Chars1), delete_leading_blanks(Chars1, Chars), atom_chars(Prompt, Chars). clean_history_prompt_chars([], []). clean_history_prompt_chars(['~', !|T], T) :- !. clean_history_prompt_chars([H|T0], [H|T]) :- clean_history_prompt_chars(T0, T). delete_leading_blanks([' '|T0], T) :- !, delete_leading_blanks(T0, T). delete_leading_blanks(L, L). %! set_default_history % % Enable !-based numbered command history. This is enabled by default % if we are not running under GNU-emacs and we do not have our own % line editing. set_default_history :- current_prolog_flag(history, _), !. set_default_history :- ( ( \+ current_prolog_flag(readline, false) ; current_prolog_flag(emacs_inferior_process, true) ) -> create_prolog_flag(history, 0, []) ; create_prolog_flag(history, 25, []) ). /******************************* * TOPLEVEL DEBUG * *******************************/ %! save_debug_after_read % % Called right after the toplevel read to save the debug status if % it was modified from the GUI thread using e.g. % % == % thread_signal(main, gdebug) % == % % @bug Ideally, the prompt would change if debug mode is enabled. % That is hard to realise with all the different console % interfaces supported by SWI-Prolog. save_debug_after_read :- current_prolog_flag(debug, true), !, save_debug. save_debug_after_read. save_debug :- ( tracing, notrace -> Tracing = true ; Tracing = false ), current_prolog_flag(debug, Debugging), set_prolog_flag(debug, false), create_prolog_flag(query_debug_settings, debug(Debugging, Tracing), []). restore_debug :- current_prolog_flag(query_debug_settings, debug(Debugging, Tracing)), set_prolog_flag(debug, Debugging), ( Tracing == true -> trace ; true ). :- initialization create_prolog_flag(query_debug_settings, debug(false, false), []). /******************************** * PROMPTING * ********************************/ '$system_prompt'(Module, BrekLev, Prompt) :- current_prolog_flag(toplevel_prompt, PAtom), atom_codes(PAtom, P0), ( Module \== user -> '$substitute'('~m', [Module, ': '], P0, P1) ; '$substitute'('~m', [], P0, P1) ), ( BrekLev > 0 -> '$substitute'('~l', ['[', BrekLev, '] '], P1, P2) ; '$substitute'('~l', [], P1, P2) ), current_prolog_flag(query_debug_settings, debug(Debugging, Tracing)), ( Tracing == true -> '$substitute'('~d', ['[trace] '], P2, P3) ; Debugging == true -> '$substitute'('~d', ['[debug] '], P2, P3) ; '$substitute'('~d', [], P2, P3) ), atom_chars(Prompt, P3). '$substitute'(From, T, Old, New) :- atom_codes(From, FromCodes), phrase(subst_chars(T), T0), '$append'(Pre, S0, Old), '$append'(FromCodes, Post, S0) -> '$append'(Pre, T0, S1), '$append'(S1, Post, New), !. '$substitute'(_, _, Old, Old). subst_chars([]) --> []. subst_chars([H|T]) --> { atomic(H), !, atom_codes(H, Codes) }, Codes, subst_chars(T). subst_chars([H|T]) --> H, subst_chars(T). /******************************** * EXECUTION * ********************************/ %! '$execute'(Goal, Bindings) is det. % % Execute Goal using Bindings. '$execute'(Var, _) :- var(Var), !, print_message(informational, var_query(Var)). '$execute'(Goal, Bindings) :- '$current_typein_module'(TypeIn), '$dwim_correct_goal'(TypeIn:Goal, Bindings, Corrected), !, setup_call_cleanup( '$set_source_module'(M0, TypeIn), expand_goal(Corrected, Expanded), '$set_source_module'(M0)), print_message(silent, toplevel_goal(Expanded, Bindings)), '$execute_goal2'(Expanded, Bindings). '$execute'(_, _) :- notrace, print_message(query, query(no)). '$execute_goal2'(Goal, Bindings) :- restore_debug, residue_vars(Goal, Vars), deterministic(Det), ( save_debug ; restore_debug, fail ), flush_output(user_output), call_expand_answer(Bindings, NewBindings), ( \+ \+ write_bindings(NewBindings, Vars, Det) -> ! ). '$execute_goal2'(_, _) :- save_debug, print_message(query, query(no)). residue_vars(Goal, Vars) :- current_prolog_flag(toplevel_residue_vars, true), !, call_residue_vars(Goal, Vars). residue_vars(Goal, []) :- toplevel_call(Goal). toplevel_call(Goal) :- call(Goal), no_lco. no_lco. %! write_bindings(+Bindings, +ResidueVars, +Deterministic) is semidet. % % Write bindings resulting from a query. The flag % prompt_alternatives_on determines whether the user is prompted % for alternatives. =groundness= gives the classical behaviour, % =determinism= is considered more adequate and informative. % % Succeeds if the user accepts the answer and fails otherwise. % % @arg ResidueVars are the residual constraints and provided if % the prolog flag `toplevel_residue_vars` is set to % `project`. write_bindings(Bindings, ResidueVars, Det) :- '$current_typein_module'(TypeIn), translate_bindings(Bindings, Bindings1, ResidueVars, TypeIn:Residuals), write_bindings2(Bindings1, Residuals, Det). write_bindings2([], Residuals, _) :- current_prolog_flag(prompt_alternatives_on, groundness), !, print_message(query, query(yes(Residuals))). write_bindings2(Bindings, Residuals, true) :- current_prolog_flag(prompt_alternatives_on, determinism), !, print_message(query, query(yes(Bindings, Residuals))). write_bindings2(Bindings, Residuals, _Det) :- repeat, print_message(query, query(more(Bindings, Residuals))), get_respons(Action), ( Action == redo -> !, fail ; Action == show_again -> fail ; !, print_message(query, query(done)) ). %! residual_goals(:NonTerminal) % % Directive that registers NonTerminal as a collector for residual % goals. :- multifile residual_goal_collector/1. :- meta_predicate residual_goals(2). residual_goals(NonTerminal) :- throw(error(context_error(nodirective, residual_goals(NonTerminal)), _)). system:term_expansion((:- residual_goals(NonTerminal)), '$toplevel':residual_goal_collector(M2:Head)) :- prolog_load_context(module, M), strip_module(M:NonTerminal, M2, Head), '$must_be'(callable, Head). %! prolog:residual_goals// is det. % % DCG that collects residual goals that are not associated with % the answer through attributed variables. :- public prolog:residual_goals//0. prolog:residual_goals --> { findall(NT, residual_goal_collector(NT), NTL) }, collect_residual_goals(NTL). collect_residual_goals([]) --> []. collect_residual_goals([H|T]) --> ( call(H) -> [] ; [] ), collect_residual_goals(T). %! prolog:translate_bindings(+Bindings0, -Bindings, +ResidueVars, %! +ResidualGoals, -Residuals) is det. % % Translate the raw variable bindings resulting from successfully % completing a query into a binding list and list of residual % goals suitable for human consumption. % % @arg Bindings is a list of binding(Vars,Value,Substitutions), % where Vars is a list of variable names. E.g. % binding(['A','B'],42,[])` means that both the variable % A and B have the value 42. Values may contain terms % '$VAR'(Name) to indicate sharing with a given variable. % Value is always an acyclic term. If cycles appear in the % answer, Substitutions contains a list of substitutions % that restore the original term. % % @arg Residuals is a pair of two lists representing residual % goals. The first element of the pair are residuals % related to the query variables and the second are % related that are disconnected from the query. :- public prolog:translate_bindings/5. :- meta_predicate prolog:translate_bindings(+, -, +, +, :). prolog:translate_bindings(Bindings0, Bindings, ResVars, ResGoals, Residuals) :- translate_bindings(Bindings0, Bindings, ResVars, ResGoals, Residuals). translate_bindings(Bindings0, Bindings, ResidueVars, Residuals) :- prolog:residual_goals(ResidueGoals, []), translate_bindings(Bindings0, Bindings, ResidueVars, ResidueGoals, Residuals). translate_bindings(Bindings0, Bindings, [], [], _:[]-[]) :- term_attvars(Bindings0, []), !, join_same_bindings(Bindings0, Bindings1), factorize_bindings(Bindings1, Bindings2), bind_vars(Bindings2, Bindings3), filter_bindings(Bindings3, Bindings). translate_bindings(Bindings0, Bindings, ResidueVars, ResGoals0, TypeIn:Residuals-HiddenResiduals) :- project_constraints(Bindings0, ResidueVars), hidden_residuals(ResidueVars, Bindings0, HiddenResiduals0), omit_qualifiers(HiddenResiduals0, TypeIn, HiddenResiduals), copy_term(Bindings0+ResGoals0, Bindings1+ResGoals1, Residuals0), '$append'(ResGoals1, Residuals0, Residuals1), omit_qualifiers(Residuals1, TypeIn, Residuals), join_same_bindings(Bindings1, Bindings2), factorize_bindings(Bindings2, Bindings3), bind_vars(Bindings3, Bindings4), filter_bindings(Bindings4, Bindings). hidden_residuals(ResidueVars, Bindings, Goal) :- term_attvars(ResidueVars, Remaining), term_attvars(Bindings, QueryVars), subtract_vars(Remaining, QueryVars, HiddenVars), copy_term(HiddenVars, _, Goal). subtract_vars(All, Subtract, Remaining) :- sort(All, AllSorted), sort(Subtract, SubtractSorted), ord_subtract(AllSorted, SubtractSorted, Remaining). ord_subtract([], _Not, []). ord_subtract([H1|T1], L2, Diff) :- diff21(L2, H1, T1, Diff). diff21([], H1, T1, [H1|T1]). diff21([H2|T2], H1, T1, Diff) :- compare(Order, H1, H2), diff3(Order, H1, T1, H2, T2, Diff). diff12([], _H2, _T2, []). diff12([H1|T1], H2, T2, Diff) :- compare(Order, H1, H2), diff3(Order, H1, T1, H2, T2, Diff). diff3(<, H1, T1, H2, T2, [H1|Diff]) :- diff12(T1, H2, T2, Diff). diff3(=, _H1, T1, _H2, T2, Diff) :- ord_subtract(T1, T2, Diff). diff3(>, H1, T1, _H2, T2, Diff) :- diff21(T2, H1, T1, Diff). %! project_constraints(+Bindings, +ResidueVars) is det. % % Call :project_attributes/2 if the Prolog flag % `toplevel_residue_vars` is set to `project`. project_constraints(Bindings, ResidueVars) :- !, term_attvars(Bindings, AttVars), phrase(attribute_modules(AttVars), Modules0), sort(Modules0, Modules), term_variables(Bindings, QueryVars), project_attributes(Modules, QueryVars, ResidueVars). project_constraints(_, _). project_attributes([], _, _). project_attributes([M|T], QueryVars, ResidueVars) :- ( current_predicate(M:project_attributes/2), catch(M:project_attributes(QueryVars, ResidueVars), E, print_message(error, E)) -> true ; true ), project_attributes(T, QueryVars, ResidueVars). attribute_modules([]) --> []. attribute_modules([H|T]) --> { get_attrs(H, Attrs) }, attrs_modules(Attrs), attribute_modules(T). attrs_modules([]) --> []. attrs_modules(att(Module, _, More)) --> [Module], attrs_modules(More). %! join_same_bindings(Bindings0, Bindings) % % Join variables that are bound to the same value. Note that we % return the _last_ value. This is because the factorization may % be different and ultimately the names will be printed as V1 = % V2, ... VN = Value. Using the last, Value has the factorization % of VN. join_same_bindings([], []). join_same_bindings([Name=V0|T0], [[Name|Names]=V|T]) :- take_same_bindings(T0, V0, V, Names, T1), join_same_bindings(T1, T). take_same_bindings([], Val, Val, [], []). take_same_bindings([Name=V1|T0], V0, V, [Name|Names], T) :- V0 == V1, !, take_same_bindings(T0, V1, V, Names, T). take_same_bindings([Pair|T0], V0, V, Names, [Pair|T]) :- take_same_bindings(T0, V0, V, Names, T). %! omit_qualifiers(+QGoals, +TypeIn, -Goals) is det. % % Omit unneeded module qualifiers from QGoals relative to the % given module TypeIn. omit_qualifiers([], _, []). omit_qualifiers([Goal0|Goals0], TypeIn, [Goal|Goals]) :- omit_qualifier(Goal0, TypeIn, Goal), omit_qualifiers(Goals0, TypeIn, Goals). omit_qualifier(M:G0, TypeIn, G) :- M == TypeIn, !, omit_meta_qualifiers(G0, TypeIn, G). omit_qualifier(M:G0, TypeIn, G) :- predicate_property(TypeIn:G0, imported_from(M)), \+ predicate_property(G0, transparent), !, G0 = G. omit_qualifier(_:G0, _, G) :- predicate_property(G0, built_in), \+ predicate_property(G0, transparent), !, G0 = G. omit_qualifier(M:G0, _, M:G) :- atom(M), !, omit_meta_qualifiers(G0, M, G). omit_qualifier(G0, TypeIn, G) :- omit_meta_qualifiers(G0, TypeIn, G). omit_meta_qualifiers(V, _, V) :- var(V), !. omit_meta_qualifiers((QA,QB), TypeIn, (A,B)) :- !, omit_qualifier(QA, TypeIn, A), omit_qualifier(QB, TypeIn, B). omit_meta_qualifiers(freeze(V, QGoal), TypeIn, freeze(V, Goal)) :- callable(QGoal), !, omit_qualifier(QGoal, TypeIn, Goal). omit_meta_qualifiers(when(Cond, QGoal), TypeIn, when(Cond, Goal)) :- callable(QGoal), !, omit_qualifier(QGoal, TypeIn, Goal). omit_meta_qualifiers(G, _, G). %! bind_vars(+BindingsIn, -Bindings) % % Bind variables to '$VAR'(Name), so they are printed by the names % used in the query. Note that by binding in the reverse order, % variables bound to one another come out in the natural order. bind_vars(Bindings0, Bindings) :- bind_query_vars(Bindings0, Bindings, SNames), bind_skel_vars(Bindings, Bindings, SNames, 1, _). bind_query_vars([], [], []). bind_query_vars([binding(Names,Var,[Var2=Cycle])|T0], [binding(Names,Cycle,[])|T], [Name|SNames]) :- Var == Var2, % also implies var(Var) !, '$last'(Names, Name), Var = '$VAR'(Name), bind_query_vars(T0, T, SNames). bind_query_vars([B|T0], [B|T], AllNames) :- B = binding(Names,Var,Skel), bind_query_vars(T0, T, SNames), ( var(Var), \+ attvar(Var), Skel == [] -> AllNames = [Name|SNames], '$last'(Names, Name), Var = '$VAR'(Name) ; AllNames = SNames ). bind_skel_vars([], _, _, N, N). bind_skel_vars([binding(_,_,Skel)|T], Bindings, SNames, N0, N) :- bind_one_skel_vars(Skel, Bindings, SNames, N0, N1), bind_skel_vars(T, Bindings, SNames, N1, N). %! bind_one_skel_vars(+Subst, +Bindings, +VarName, +N0, -N) % % Give names to the factorized variables that do not have a name % yet. This introduces names _S, avoiding duplicates. If a % factorized variable shares with another binding, use the name of % that variable. % % @tbd Consider the call below. We could remove either of the % A = x(1). Which is best? % % == % ?- A = x(1), B = a(A,A). % A = x(1), % B = a(A, A), % where % A = x(1). % == bind_one_skel_vars([], _, _, N, N). bind_one_skel_vars([Var=Value|T], Bindings, Names, N0, N) :- ( var(Var) -> ( '$member'(binding(Names, VVal, []), Bindings), same_term(Value, VVal) -> '$last'(Names, VName), Var = '$VAR'(VName), N2 = N0 ; between(N0, infinite, N1), atom_concat('_S', N1, Name), \+ memberchk(Name, Names), !, Var = '$VAR'(Name), N2 is N1 + 1 ) ; N2 = N0 ), bind_one_skel_vars(T, Bindings, Names, N2, N). %! factorize_bindings(+Bindings0, -Factorized) % % Factorize cycles and sharing in the bindings. factorize_bindings([], []). factorize_bindings([Name=Value|T0], [binding(Name, Skel, Subst)|T]) :- '$factorize_term'(Value, Skel, Subst0), ( current_prolog_flag(toplevel_print_factorized, true) -> Subst = Subst0 ; only_cycles(Subst0, Subst) ), factorize_bindings(T0, T). only_cycles([], []). only_cycles([B|T0], List) :- ( B = (Var=Value), Var = Value, acyclic_term(Var) -> only_cycles(T0, List) ; List = [B|T], only_cycles(T0, T) ). %! filter_bindings(+Bindings0, -Bindings) % % Remove bindings that must not be printed. There are two of them: % Variables whose name start with '_' and variables that are only % bound to themselves (or, unbound). filter_bindings([], []). filter_bindings([H0|T0], T) :- hide_vars(H0, H), ( ( arg(1, H, []) ; self_bounded(H) ) -> filter_bindings(T0, T) ; T = [H|T1], filter_bindings(T0, T1) ). hide_vars(binding(Names0, Skel, Subst), binding(Names, Skel, Subst)) :- hide_names(Names0, Skel, Subst, Names). hide_names([], _, _, []). hide_names([Name|T0], Skel, Subst, T) :- ( sub_atom(Name, 0, _, _, '_'), current_prolog_flag(toplevel_print_anon, false), sub_atom(Name, 1, 1, _, Next), char_type(Next, prolog_var_start) -> true ; Subst == [], Skel == '$VAR'(Name) ), !, hide_names(T0, Skel, Subst, T). hide_names([Name|T0], Skel, Subst, [Name|T]) :- hide_names(T0, Skel, Subst, T). self_bounded(binding([Name], Value, [])) :- Value == '$VAR'(Name). %! get_respons(-Action) % % Read the continuation entered by the user. get_respons(Action) :- repeat, flush_output(user_output), get_single_char(Char), answer_respons(Char, Action), ( Action == again -> print_message(query, query(action)), fail ; ! ). answer_respons(Char, again) :- '$in_reply'(Char, '?h'), !, print_message(help, query(help)). answer_respons(Char, redo) :- '$in_reply'(Char, ';nrNR \t'), !, print_message(query, if_tty([ansi(bold, ';', [])])). answer_respons(Char, redo) :- '$in_reply'(Char, 'tT'), !, trace, save_debug, print_message(query, if_tty([ansi(bold, '; [trace]', [])])). answer_respons(Char, continue) :- '$in_reply'(Char, 'ca\n\ryY.'), !, print_message(query, if_tty([ansi(bold, '.', [])])). answer_respons(0'b, show_again) :- !, break. answer_respons(Char, show_again) :- print_predicate(Char, Pred, Options), !, print_message(query, if_tty(['~w'-[Pred]])), set_prolog_flag(answer_write_options, Options). answer_respons(-1, show_again) :- !, print_message(query, halt('EOF')), halt(0). answer_respons(Char, again) :- print_message(query, no_action(Char)). print_predicate(0'w, [write], [ quoted(true), spacing(next_argument) ]). print_predicate(0'p, [print], [ quoted(true), portray(true), max_depth(10), spacing(next_argument) ]). /******************************* * EXPANSION * *******************************/ :- user:dynamic(expand_query/4). :- user:multifile(expand_query/4). call_expand_query(Goal, Expanded, Bindings, ExpandedBindings) :- user:expand_query(Goal, Expanded, Bindings, ExpandedBindings), !. call_expand_query(Goal, Expanded, Bindings, ExpandedBindings) :- toplevel_variables:expand_query(Goal, Expanded, Bindings, ExpandedBindings), !. call_expand_query(Goal, Goal, Bindings, Bindings). :- user:dynamic(expand_answer/2). :- user:multifile(expand_answer/2). call_expand_answer(Goal, Expanded) :- user:expand_answer(Goal, Expanded), !. call_expand_answer(Goal, Expanded) :- toplevel_variables:expand_answer(Goal, Expanded), !. call_expand_answer(Goal, Goal).