/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (C): 1985-2014, University of Amsterdam VU University Amsterdam This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA As a special exception, if you link this library with other files, compiled with a Free Software compiler, to produce an executable, this library does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License. */ :- module('$toplevel', [ '$initialise'/0, % start Prolog '$toplevel'/0, % Prolog top-level (re-entrant) '$compile'/0, % `-c' toplevel version/0, % Write initial banner version/1, % Add message to the banner prolog/0, % user toplevel predicate '$query_loop'/0, % toplevel predicate (initialization)/1, % initialization goal (directive) '$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'. /******************************* * 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. % % Updated 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', 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), '$cmd_option_val'(goal, GoalAtom), term_to_atom(Goal, GoalAtom), ignore(user:Goal). init_debug_flags :- once(print_predicate(_, [print], PrintOptions)), create_prolog_flag(answer_write_options, PrintOptions, []), create_prolog_flag(prompt_alternatives_on, determinism, []), create_prolog_flag(toplevel_extra_white_line, true, []), create_prolog_flag(toplevel_print_factorized, false, []), create_prolog_flag(print_write_options, [ portray(true), quoted(true), numbervars(true) ], []), create_prolog_flag(toplevel_residue_vars, false, []), '$set_debugger_write_options'(print). %% setup_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) -> catch(load_files(user:library(ansi_term), [silent(true), if(not_loaded)]), _, true) ; true ). setup_history :- ( stream_property(user_input, tty(true)), current_predicate(rl_add_history/1), \+ current_prolog_flag(save_history, false), catch(load_files(library(prolog_history), [silent(true)]), _, fail) -> prolog_history(enable) ; true ). :- '$hide'('$toplevel'/0). % avoid in the GUI stacktrace %% '$toplevel'/0 % % Called from PL_toplevel() '$toplevel' :- '$runtoplevel', print_message(informational, halt). %% '$runtoplevel' % % Actually run the toplevel. If there is a syntax error in the % goal there is no reason to persue. Something like that should % happen to repetitive exceptions in the toplevel as well, but how % do we distinguish between interactive usage that frequently % raises and error and a program crashing in a loop? % % @see prolog/0 is the default interactive toplevel '$runtoplevel' :- '$cmd_option_val'(toplevel, TopLevelAtom), catch(term_to_atom(TopLevel0, TopLevelAtom), E, (print_message(error, E), halt(1))), toplevel_goal(TopLevel0, TopLevel), user:TopLevel. toplevel_goal(prolog, '$query_loop') :- !, catch(setup_colors, E, print_message(warning, E)), catch(setup_history, E, print_message(warning, E)). toplevel_goal(Goal, Goal). %% '$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. %% '$query_loop' % % Run the normal Prolog query loop. Note that the query is not % protected by catch/3. Dealing with unhandled exceptions is done % by the C-function query_loop(). This ensures that unhandled % exceptions are really unhandled (in Prolog). '$query_loop' :- ( current_prolog_flag(break_level, BreakLev) -> true ; BreakLev = -1 ), repeat, ( '$module'(TypeIn, TypeIn), ( stream_property(user_input, tty(true)) -> '$system_prompt'(TypeIn, BreakLev, Prompt), prompt(Old, '| ') ; Prompt = '', prompt(Old, '') ), trim_stacks, read_query(Prompt, Query, Bindings), prompt(_, Old), call_expand_query(Query, ExpandedQuery, Bindings, ExpandedBindings) -> expand_goal(ExpandedQuery, Goal), '$execute'(Goal, ExpandedBindings) ), !. read_query(Prompt, Goal, Bindings) :- current_prolog_flag(history, N), integer(N), N > 0, !, read_history(h, '!h', [trace, end_of_file], Prompt, Goal, Bindings). read_query(Prompt, Goal, Bindings) :- remove_history_prompt(Prompt, Prompt1), repeat, % over syntax errors prompt1(Prompt1), read_query_line(user_input, Line), ( Line \== end_of_file, current_predicate(_, user:rl_add_history(_)) -> format(atom(CompleteLine), '~W~W', [ Line, [partial(true)], '.', [partial(true)] ]), call(user:rl_add_history(CompleteLine)) ; true ), '$module'(TypeIn, TypeIn), catch(read_term_from_atom(Line, Goal, [ variable_names(Bindings), module(TypeIn) ]), E, ( print_message(error, E), fail )), !, '$save_history'(Line). %% read_query_line(+Input, -Line) is det. read_query_line(Input, Line) :- catch(read_term_as_atom(Input, Line), Error, true), save_debug_after_read, ( var(Error) -> true ; Error = error(syntax_error(_),_) -> print_message(error, Error), fail ; print_message(error, Error), throw(Error) ). %% read_term_as_atom(+Input, -Line) % % Read the next term as an atom and skip to the newline or a % non-space character. read_term_as_atom(In, Line) :- '$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 :- ( ( current_prolog_flag(readline, true) ; current_prolog_flag(emacs_inferior_process, true) ) -> create_prolog_flag(history, 0, []) ; create_prolog_flag(history, 25, []) ). :- initialization set_default_history. /******************************* * 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 * ********************************/ '$execute'(Var, _) :- var(Var), !, print_message(informational, var_query(Var)), fail. '$execute'(end_of_file, _) :- !, print_message(query, query(eof)). '$execute'(Goal, Bindings) :- '$module'(TypeIn, 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). '$execute'(_, _) :- notrace, print_message(query, query(no)), fail. '$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) -> !, fail ). '$execute_goal2'(_, _) :- save_debug, print_message(query, query(no)), fail. residue_vars(Goal, Vars) :- current_prolog_flag(toplevel_residue_vars, true), !, call_residue_vars(Goal, Vars). residue_vars(Goal, []) :- call(Goal). %% write_bindings(+Bindings, +ResidueVars, +Deterministic) % % Write bindings resulting from a query. The flag % prompt_alternatives_on determines whether the user is prompted % for alternatives. =groundness= gives the classical behaviour, % =determinism= is considered more adequate and informative. % % @arg ResidueVars are the residual constraints and provided if % the prolog flag `toplevel_residue_vars` is set to % `project`. write_bindings(Bindings, ResidueVars, Det) :- '$module'(TypeIn, 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)) ). %% prolog:translate_bindings(+Bindings0, -Bindings, +ResidueVars, %% -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/4. :- meta_predicate prolog:translate_bindings(+, -, +, :). prolog:translate_bindings(Bindings0, Bindings, ResidueVars, Residuals) :- translate_bindings(Bindings0, Bindings, ResidueVars, 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, TypeIn:Residuals-HiddenResiduals) :- project_constraints(Bindings0, ResidueVars), hidden_residuals(ResidueVars, Bindings0, HiddenResiduals0), omit_qualifiers(HiddenResiduals0, TypeIn, HiddenResiduals), copy_term(Bindings0, Bindings1, Residuals0), omit_qualifiers(Residuals0, 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, 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, Goal).