1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  1997-2018, University of Amsterdam
    7                              VU University Amsterdam
    8    All rights reserved.
    9
   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
   13
   14    1. Redistributions of source code must retain the above copyright
   15       notice, this list of conditions and the following disclaimer.
   16
   17    2. Redistributions in binary form must reproduce the above copyright
   18       notice, this list of conditions and the following disclaimer in
   19       the documentation and/or other materials provided with the
   20       distribution.
   21
   22    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   23    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   24    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   25    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   26    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   27    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   28    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   29    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   30    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   32    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   33    POSSIBILITY OF SUCH DAMAGE.
   34*/
   35
   36:- module('$messages',
   37          [ print_message/2,            % +Kind, +Term
   38            print_message_lines/3,      % +Stream, +Prefix, +Lines
   39            message_to_string/2         % +Term, -String
   40          ]).   41
   42:- multifile
   43    prolog:message//1,              % entire message
   44    prolog:error_message//1,        % 1-st argument of error term
   45    prolog:message_context//1,      % Context of error messages
   46    prolog:message_location//1,     % (File) location of error messages
   47    prolog:message_line_element/2.  % Extend printing
   48:- discontiguous
   49    prolog_message/3.   50
   51:- public
   52    translate_message//1.   53
   54:- create_prolog_flag(message_context, [thread], []).

 translate_message(+Term)// is det

Translate a message Term into message lines. The produced lines is a list of

nl

Emit a newline

Fmt - Args

Emit the result of format(Fmt, Args)

Fmt

Emit the result of format(Fmt)

flush

Used only as last element of the list. Simply flush the output instead of producing a final newline.

at_same_line

Start the messages at the same line (instead of using ~N)

   73translate_message(Term) -->
   74    translate_message2(Term),
   75    !.
   76translate_message(Term) -->
   77    { Term = error(_, _) },
   78    [ 'Unknown exception: ~p'-[Term] ].
   79translate_message(Term) -->
   80    [ 'Unknown message: ~p'-[Term] ].
   81
   82translate_message2(Term) -->
   83    {var(Term)},
   84    !,
   85    [ 'Unknown message: ~p'-[Term] ].
   86translate_message2(Term) -->
   87    prolog:message(Term).
   88translate_message2(Term) -->
   89    prolog_message(Term).
   90translate_message2(error(resource_error(stack), Context)) -->
   91    out_of_stack(Context).
   92translate_message2(error(resource_error(Missing), _)) -->
   93    [ 'Not enough resources: ~w'-[Missing] ].
   94translate_message2(error(ISO, SWI)) -->
   95    swi_location(SWI),
   96    term_message(ISO),
   97    swi_extra(SWI).
   98translate_message2('$aborted') -->
   99    [ 'Execution Aborted' ].
  100translate_message2(message_lines(Lines), L, T) :- % deal with old C-warning()
  101    make_message_lines(Lines, L, T).
  102translate_message2(format(Fmt, Args)) -->
  103    [ Fmt-Args ].
  104
  105make_message_lines([], T, T) :- !.
  106make_message_lines([Last],  ['~w'-[Last]|T], T) :- !.
  107make_message_lines([L0|LT], ['~w'-[L0],nl|T0], T) :-
  108    make_message_lines(LT, T0, T).
  109
  110term_message(Term) -->
  111    {var(Term)},
  112    !,
  113    [ 'Unknown error term: ~p'-[Term] ].
  114term_message(Term) -->
  115    prolog:error_message(Term).
  116term_message(Term) -->
  117    iso_message(Term).
  118term_message(Term) -->
  119    swi_message(Term).
  120term_message(Term) -->
  121    [ 'Unknown error term: ~p'-[Term] ].
  122
  123iso_message(type_error(evaluable, Actual)) -->
  124    { callable(Actual) },
  125    [ 'Arithmetic: `~p'' is not a function'-[Actual] ].
  126iso_message(type_error(free_of_attvar, Actual)) -->
  127    [ 'Type error: `~W'' contains attributed variables'-
  128      [Actual,[portray(true), attributes(portray)]] ].
  129iso_message(type_error(Expected, Actual)) -->
  130    [ 'Type error: `~w'' expected, found `~p'''-[Expected, Actual] ],
  131    type_error_comment(Expected, Actual).
  132iso_message(domain_error(Domain, Actual)) -->
  133    [ 'Domain error: '-[] ], domain(Domain),
  134    [ ' expected, found `~p'''-[Actual] ].
  135iso_message(instantiation_error) -->
  136    [ 'Arguments are not sufficiently instantiated' ].
  137iso_message(uninstantiation_error(Var)) -->
  138    [ 'Uninstantiated argument expected, found ~p'-[Var] ].
  139iso_message(representation_error(What)) -->
  140    [ 'Cannot represent due to `~w'''-[What] ].
  141iso_message(permission_error(Action, Type, Object)) -->
  142    permission_error(Action, Type, Object).
  143iso_message(evaluation_error(Which)) -->
  144    [ 'Arithmetic: evaluation error: `~p'''-[Which] ].
  145iso_message(existence_error(procedure, Proc)) -->
  146    [ 'Undefined procedure: ~q'-[Proc] ],
  147    undefined_proc_msg(Proc).
  148iso_message(existence_error(answer_variable, Var)) -->
  149    [ '$~w was not bound by a previous query'-[Var] ].
  150iso_message(existence_error(Type, Object)) -->
  151    [ '~w `~p'' does not exist'-[Type, Object] ].
  152iso_message(existence_error(Type, Object, In)) --> % not ISO
  153    [ '~w `~p'' does not exist in ~p'-[Type, Object, In] ].
  154iso_message(busy(Type, Object)) -->
  155    [ '~w `~p'' is busy'-[Type, Object] ].
  156iso_message(syntax_error(swi_backslash_newline)) -->
  157    [ 'Deprecated ... \\<newline><white>*.  Use \\c' ].
  158iso_message(syntax_error(Id)) -->
  159    [ 'Syntax error: ' ],
  160    syntax_error(Id).
  161iso_message(occurs_check(Var, In)) -->
  162    [ 'Cannot unify ~p with ~p: would create an infinite tree'-[Var, In] ].

 permission_error(Action, Type, Object)//

Translate permission errors. Most follow te pattern "No permission to Action Type Object", but some are a bit different.

  169permission_error(Action, built_in_procedure, Pred) -->
  170    { user_predicate_indicator(Pred, PI)
  171    },
  172    [ 'No permission to ~w built-in predicate `~p'''-[Action, PI] ],
  173    (   {Action \== export}
  174    ->  [ nl,
  175          'Use :- redefine_system_predicate(+Head) if redefinition is intended'
  176        ]
  177    ;   []
  178    ).
  179permission_error(import_into(Dest), procedure, Pred) -->
  180    [ 'No permission to import ~p into ~w'-[Pred, Dest] ].
  181permission_error(Action, static_procedure, Proc) -->
  182    [ 'No permission to ~w static procedure `~p'''-[Action, Proc] ],
  183    defined_definition('Defined', Proc).
  184permission_error(input, stream, Stream) -->
  185    [ 'No permission to read from output stream `~p'''-[Stream] ].
  186permission_error(output, stream, Stream) -->
  187    [ 'No permission to write to input stream `~p'''-[Stream] ].
  188permission_error(input, text_stream, Stream) -->
  189    [ 'No permission to read bytes from TEXT stream `~p'''-[Stream] ].
  190permission_error(output, text_stream, Stream) -->
  191    [ 'No permission to write bytes to TEXT stream `~p'''-[Stream] ].
  192permission_error(input, binary_stream, Stream) -->
  193    [ 'No permission to read characters from binary stream `~p'''-[Stream] ].
  194permission_error(output, binary_stream, Stream) -->
  195    [ 'No permission to write characters to binary stream `~p'''-[Stream] ].
  196permission_error(open, source_sink, alias(Alias)) -->
  197    [ 'No permission to reuse alias "~p": already taken'-[Alias] ].
  198permission_error(Action, Type, Object) -->
  199    [ 'No permission to ~w ~w `~p'''-[Action, Type, Object] ].
  200
  201
  202undefined_proc_msg(_:(^)/2) -->
  203    !,
  204    undefined_proc_msg((^)/2).
  205undefined_proc_msg((^)/2) -->
  206    !,
  207    [nl, '  ^/2 can only appear as the 2nd argument of setof/3 and bagof/3'].
  208undefined_proc_msg((:-)/2) -->
  209    !,
  210    [nl, '  Rules must be loaded from a file'],
  211    faq('ToplevelMode').
  212undefined_proc_msg((:-)/1) -->
  213    !,
  214    [nl, '  Directives must be loaded from a file'],
  215    faq('ToplevelMode').
  216undefined_proc_msg((?-)/1) -->
  217    !,
  218    [nl, '  ?- is the Prolog prompt'],
  219    faq('ToplevelMode').
  220undefined_proc_msg(Proc) -->
  221    { dwim_predicates(Proc, Dwims) },
  222    (   {Dwims \== []}
  223    ->  [nl, '  However, there are definitions for:', nl],
  224        dwim_message(Dwims)
  225    ;   []
  226    ).
  227
  228faq(Page) -->
  229    [nl, '  See FAQ at http://www.swi-prolog.org/FAQ/', Page, '.txt' ].
  230
  231type_error_comment(_Expected, Actual) -->
  232    { type_of(Actual, Type),
  233      (   sub_atom(Type, 0, 1, _, First),
  234          memberchk(First, [a,e,i,o,u])
  235      ->  Article = an
  236      ;   Article = a
  237      )
  238    },
  239    [ ' (~w ~w)'-[Article, Type] ].
  240
  241type_of(Term, Type) :-
  242    (   attvar(Term)      -> Type = attvar
  243    ;   var(Term)         -> Type = var
  244    ;   atom(Term)        -> Type = atom
  245    ;   integer(Term)     -> Type = integer
  246    ;   string(Term)      -> Type = string
  247    ;   Term == []        -> Type = empty_list
  248    ;   blob(Term, BlobT) -> blob_type(BlobT, Type)
  249    ;   rational(Term)    -> Type = rational
  250    ;   float(Term)       -> Type = float
  251    ;   is_stream(Term)   -> Type = stream
  252    ;   is_dict(Term)     -> Type = dict
  253    ;   is_list(Term)     -> Type = list
  254    ;   cyclic_term(Term) -> Type = cyclic
  255    ;   compound(Term)    -> Type = compound
  256    ;                        Type = unknown
  257    ).
  258
  259blob_type(BlobT, Type) :-
  260    atom_concat(BlobT, '_reference', Type).
  261
  262syntax_error(end_of_clause) -->
  263    [ 'Unexpected end of clause' ].
  264syntax_error(end_of_clause_expected) -->
  265    [ 'End of clause expected' ].
  266syntax_error(end_of_file) -->
  267    [ 'Unexpected end of file' ].
  268syntax_error(end_of_file_in_block_comment) -->
  269    [ 'End of file in /* ... */ comment' ].
  270syntax_error(end_of_file_in_quoted(Quote)) -->
  271    [ 'End of file in quoted ' ],
  272    quoted_type(Quote).
  273syntax_error(illegal_number) -->
  274    [ 'Illegal number' ].
  275syntax_error(long_atom) -->
  276    [ 'Atom too long (see style_check/1)' ].
  277syntax_error(long_string) -->
  278    [ 'String too long (see style_check/1)' ].
  279syntax_error(operator_clash) -->
  280    [ 'Operator priority clash' ].
  281syntax_error(operator_expected) -->
  282    [ 'Operator expected' ].
  283syntax_error(operator_balance) -->
  284    [ 'Unbalanced operator' ].
  285syntax_error(quoted_punctuation) -->
  286    [ 'Operand expected, unquoted comma or bar found' ].
  287syntax_error(list_rest) -->
  288    [ 'Unexpected comma or bar in rest of list' ].
  289syntax_error(cannot_start_term) -->
  290    [ 'Illegal start of term' ].
  291syntax_error(punct(Punct, End)) -->
  292    [ 'Unexpected `~w\' before `~w\''-[Punct, End] ].
  293syntax_error(undefined_char_escape(C)) -->
  294    [ 'Undefined character escape in quoted atom or string: `\\~w\''-[C] ].
  295syntax_error(void_not_allowed) -->
  296    [ 'Empty argument list "()"' ].
  297syntax_error(Message) -->
  298    [ '~w'-[Message] ].
  299
  300quoted_type('\'') --> [atom].
  301quoted_type('\"') --> { current_prolog_flag(double_quotes, Type) }, [Type-[]].
  302quoted_type('\`') --> { current_prolog_flag(back_quotes, Type) }, [Type-[]].
  303
  304domain(range(Low,High)) -->
  305    !,
  306    ['[~q..~q]'-[Low,High] ].
  307domain(Domain) -->
  308    ['`~w\''-[Domain] ].
  309
  310dwim_predicates(Module:Name/_Arity, Dwims) :-
  311    !,
  312    findall(Dwim, dwim_predicate(Module:Name, Dwim), Dwims).
  313dwim_predicates(Name/_Arity, Dwims) :-
  314    findall(Dwim, dwim_predicate(user:Name, Dwim), Dwims).
  315
  316dwim_message([]) --> [].
  317dwim_message([M:Head|T]) -->
  318    { hidden_module(M),
  319      !,
  320      functor(Head, Name, Arity)
  321    },
  322    [ '        ~q'-[Name/Arity], nl ],
  323    dwim_message(T).
  324dwim_message([Module:Head|T]) -->
  325    !,
  326    { functor(Head, Name, Arity)
  327    },
  328    [ '        ~q'-[Module:Name/Arity], nl],
  329    dwim_message(T).
  330dwim_message([Head|T]) -->
  331    {functor(Head, Name, Arity)},
  332    [ '        ~q'-[Name/Arity], nl],
  333    dwim_message(T).
  334
  335
  336swi_message(io_error(Op, Stream)) -->
  337    [ 'I/O error in ~w on stream ~p'-[Op, Stream] ].
  338swi_message(shell(execute, Cmd)) -->
  339    [ 'Could not execute `~w'''-[Cmd] ].
  340swi_message(shell(signal(Sig), Cmd)) -->
  341    [ 'Caught signal ~d on `~w'''-[Sig, Cmd] ].
  342swi_message(format(Fmt, Args)) -->
  343    [ Fmt-Args ].
  344swi_message(signal(Name, Num)) -->
  345    [ 'Caught signal ~d (~w)'-[Num, Name] ].
  346swi_message(limit_exceeded(Limit, MaxVal)) -->
  347    [ 'Exceeded ~w limit (~w)'-[Limit, MaxVal] ].
  348swi_message(goal_failed(Goal)) -->
  349    [ 'goal unexpectedly failed: ~p'-[Goal] ].
  350swi_message(shared_object(_Action, Message)) --> % Message = dlerror()
  351    [ '~w'-[Message] ].
  352swi_message(system_error(Error)) -->
  353    [ 'error in system call: ~w'-[Error]
  354    ].
  355swi_message(system_error) -->
  356    [ 'error in system call'
  357    ].
  358swi_message(failure_error(Goal)) -->
  359    [ 'Goal failed: ~p'-[Goal] ].
  360swi_message(timeout_error(Op, Stream)) -->
  361    [ 'Timeout in ~w from ~p'-[Op, Stream] ].
  362swi_message(not_implemented(Type, What)) -->
  363    [ '~w `~p\' is not implemented in this version'-[Type, What] ].
  364swi_message(context_error(nodirective, Goal)) -->
  365    { goal_to_predicate_indicator(Goal, PI) },
  366    [ 'Wrong context: ~p can only be used in a directive'-[PI] ].
  367swi_message(context_error(edit, no_default_file)) -->
  368    (   { current_prolog_flag(windows, true) }
  369    ->  [ 'Edit/0 can only be used after opening a \c
  370               Prolog file by double-clicking it' ]
  371    ;   [ 'Edit/0 can only be used with the "-s file" commandline option'
  372        ]
  373    ),
  374    [ nl, 'Use "?- edit(Topic)." or "?- emacs."' ].
  375swi_message(context_error(function, meta_arg(S))) -->
  376    [ 'Functions are not (yet) supported for meta-arguments of type ~q'-[S] ].
  377swi_message(format_argument_type(Fmt, Arg)) -->
  378    [ 'Illegal argument to format sequence ~~~w: ~p'-[Fmt, Arg] ].
  379swi_message(format(Msg)) -->
  380    [ 'Format error: ~w'-[Msg] ].
  381swi_message(conditional_compilation_error(unterminated, Where)) -->
  382    [ 'Unterminated conditional compilation from '-[] ],
  383    cond_location(Where).
  384swi_message(conditional_compilation_error(no_if, What)) -->
  385    [ ':- ~w without :- if'-[What] ].
  386swi_message(duplicate_key(Key)) -->
  387    [ 'Duplicate key: ~p'-[Key] ].
  388swi_message(initialization_error(failed, Goal, File:Line)) -->
  389    !,
  390    [ '~w:~w: ~p: false'-[File, Line, Goal] ].
  391swi_message(initialization_error(Error, Goal, File:Line)) -->
  392    [ '~w:~w: ~p '-[File, Line, Goal] ],
  393    translate_message(Error).
  394swi_message(qlf_format_error(File, Message)) -->
  395    [ '~w: Invalid QLF file: ~w'-[File, Message] ].
  396
  397cond_location(File:Line) -->
  398    { file_base_name(File, Base) },
  399    [ '~w:~d'-[Base, Line] ].
  400
  401swi_location(X) -->
  402    { var(X)
  403    },
  404    !,
  405    [].
  406swi_location(Context) -->
  407    prolog:message_location(Context),
  408    !.
  409swi_location(context(Caller, _Msg)) -->
  410    { ground(Caller)
  411    },
  412    !,
  413    caller(Caller).
  414swi_location(file(Path, Line, -1, _CharNo)) -->
  415    !,
  416    [ '~w:~d: '-[Path, Line] ].
  417swi_location(file(Path, Line, LinePos, _CharNo)) -->
  418    [ '~w:~d:~d: '-[Path, Line, LinePos] ].
  419swi_location(stream(Stream, Line, LinePos, CharNo)) -->
  420    (   { is_stream(Stream),
  421          stream_property(Stream, file_name(File))
  422        }
  423    ->  swi_location(file(File, Line, LinePos, CharNo))
  424    ;   [ 'Stream ~w:~d:~d '-[Stream, Line, LinePos] ]
  425    ).
  426swi_location(_) -->
  427    [].
  428
  429caller(system:'$record_clause'/3) -->
  430    !,
  431    [].
  432caller(Module:Name/Arity) -->
  433    !,
  434    (   { \+ hidden_module(Module) }
  435    ->  [ '~q:~q/~w: '-[Module, Name, Arity] ]
  436    ;   [ '~q/~w: '-[Name, Arity] ]
  437    ).
  438caller(Name/Arity) -->
  439    [ '~q/~w: '-[Name, Arity] ].
  440caller(Caller) -->
  441    [ '~p: '-[Caller] ].
  442
  443
  444swi_extra(X) -->
  445    { var(X)
  446    },
  447    !,
  448    [].
  449swi_extra(Context) -->
  450    prolog:message_context(Context).
  451swi_extra(context(_, Msg)) -->
  452    { nonvar(Msg),
  453      Msg \== ''
  454    },
  455    !,
  456    swi_comment(Msg).
  457swi_extra(string(String, CharPos)) -->
  458    { sub_string(String, 0, CharPos, _, Before),
  459      sub_string(String, CharPos, _, 0, After)
  460    },
  461    [ nl, '~w'-[Before], nl, '** here **', nl, '~w'-[After] ].
  462swi_extra(_) -->
  463    [].
  464
  465swi_comment(already_from(Module)) -->
  466    !,
  467    [ ' (already imported from ~q)'-[Module] ].
  468swi_comment(directory(_Dir)) -->
  469    !,
  470    [ ' (is a directory)' ].
  471swi_comment(not_a_directory(_Dir)) -->
  472    !,
  473    [ ' (is not a directory)' ].
  474swi_comment(Msg) -->
  475    [ ' (~w)'-[Msg] ].
  476
  477
  478thread_context -->
  479    { thread_self(Me), Me \== main, thread_property(Me, id(Id)) },
  480    !,
  481    ['[Thread ~w] '-[Id]].
  482thread_context -->
  483    [].
  484
  485                 /*******************************
  486                 *        NORMAL MESSAGES       *
  487                 *******************************/
  488
  489prolog_message(initialization_error(_, E, File:Line)) -->
  490    !,
  491    [ '~w:~d: '-[File, Line],
  492      'Initialization goal raised exception:', nl
  493    ],
  494    translate_message(E).
  495prolog_message(initialization_error(Goal, E, _)) -->
  496    [ 'Initialization goal ~p raised exception:'-[Goal], nl ],
  497    translate_message(E).
  498prolog_message(initialization_failure(_Goal, File:Line)) -->
  499    !,
  500    [ '~w:~d: '-[File, Line],
  501      'Initialization goal failed'-[]
  502    ].
  503prolog_message(initialization_failure(Goal, _)) -->
  504    [ 'Initialization goal failed: ~p'-[Goal]
  505    ].
  506prolog_message(initialization_exception(E)) -->
  507    [ 'Prolog initialisation failed:', nl ],
  508    translate_message(E).
  509prolog_message(init_goal_syntax(Error, Text)) -->
  510    !,
  511    [ '-g ~w: '-[Text] ],
  512    translate_message(Error).
  513prolog_message(init_goal_failed(failed, @(Goal,File:Line))) -->
  514    !,
  515    [ '~w:~w: ~p: false'-[File, Line, Goal] ].
  516prolog_message(init_goal_failed(Error, @(Goal,File:Line))) -->
  517    !,
  518    [ '~w:~w: ~p '-[File, Line, Goal] ],
  519    translate_message(Error).
  520prolog_message(init_goal_failed(failed, Text)) -->
  521    !,
  522    [ '-g ~w: false'-[Text] ].
  523prolog_message(init_goal_failed(Error, Text)) -->
  524    !,
  525    [ '-g ~w: '-[Text] ],
  526    translate_message(Error).
  527prolog_message(unhandled_exception(E)) -->
  528    [ 'Unhandled exception: ' ],
  529    (   translate_message2(E)
  530    ->  []
  531    ;   [ '~p'-[E] ]
  532    ).
  533prolog_message(goal_failed(Context, Goal)) -->
  534    [ 'Goal (~w) failed: ~p'-[Context, Goal] ].
  535prolog_message(no_current_module(Module)) -->
  536    [ '~w is not a current module (created)'-[Module] ].
  537prolog_message(commandline_arg_type(Flag, Arg)) -->
  538    [ 'Bad argument to commandline option -~w: ~w'-[Flag, Arg] ].
  539prolog_message(missing_feature(Name)) -->
  540    [ 'This version of SWI-Prolog does not support ~w'-[Name] ].
  541prolog_message(singletons(_Term, List)) -->
  542    [ 'Singleton variables: ~w'-[List] ].
  543prolog_message(multitons(_Term, List)) -->
  544    [ 'Singleton-marked variables appearing more than once: ~w'-[List] ].
  545prolog_message(profile_no_cpu_time) -->
  546    [ 'No CPU-time info.  Check the SWI-Prolog manual for details' ].
  547prolog_message(non_ascii(Text, Type)) -->
  548    [ 'Unquoted ~w with non-portable characters: ~w'-[Type, Text] ].
  549prolog_message(io_warning(Stream, Message)) -->
  550    { stream_property(Stream, position(Position)),
  551      !,
  552      stream_position_data(line_count, Position, LineNo),
  553      stream_position_data(line_position, Position, LinePos),
  554      (   stream_property(Stream, file_name(File))
  555      ->  Obj = File
  556      ;   Obj = Stream
  557      )
  558    },
  559    [ '~p:~d:~d: ~w'-[Obj, LineNo, LinePos, Message] ].
  560prolog_message(io_warning(Stream, Message)) -->
  561    [ 'stream ~p: ~w'-[Stream, Message] ].
  562prolog_message(option_usage(pldoc)) -->
  563    [ 'Usage: --pldoc[=port]' ].
  564prolog_message(interrupt(begin)) -->
  565    [ 'Action (h for help) ? ', flush ].
  566prolog_message(interrupt(end)) -->
  567    [ 'continue' ].
  568prolog_message(interrupt(trace)) -->
  569    [ 'continue (trace mode)' ].
  570prolog_message(unknown_in_module_user) -->
  571    [ 'Using a non-error value for unknown in the global module', nl,
  572      'causes most of the development environment to stop working.', nl,
  573      'Please use :- dynamic or limit usage of unknown to a module.', nl,
  574      'See http://www.swi-prolog.org/howto/database.html'
  575    ].
  576prolog_message(deprecated(What)) -->
  577    deprecated(What).
  578
  579
  580                 /*******************************
  581                 *         LOADING FILES        *
  582                 *******************************/
  583
  584prolog_message(modify_active_procedure(Who, What)) -->
  585    [ '~p: modified active procedure ~p'-[Who, What] ].
  586prolog_message(load_file(failed(user:File))) -->
  587    [ 'Failed to load ~p'-[File] ].
  588prolog_message(load_file(failed(Module:File))) -->
  589    [ 'Failed to load ~p into module ~p'-[File, Module] ].
  590prolog_message(load_file(failed(File))) -->
  591    [ 'Failed to load ~p'-[File] ].
  592prolog_message(mixed_directive(Goal)) -->
  593    [ 'Cannot pre-compile mixed load/call directive: ~p'-[Goal] ].
  594prolog_message(cannot_redefine_comma) -->
  595    [ 'Full stop in clause-body?  Cannot redefine ,/2' ].
  596prolog_message(illegal_autoload_index(Dir, Term)) -->
  597    [ 'Illegal term in INDEX file of directory ~w: ~w'-[Dir, Term] ].
  598prolog_message(redefined_procedure(Type, Proc)) -->
  599    [ 'Redefined ~w procedure ~p'-[Type, Proc] ],
  600    defined_definition('Previously defined', Proc).
  601prolog_message(declare_module(Module, abolish(Predicates))) -->
  602    [ 'Loading module ~w abolished: ~p'-[Module, Predicates] ].
  603prolog_message(import_private(Module, Private)) -->
  604    [ 'import/1: ~p is not exported (still imported into ~q)'-
  605      [Private, Module]
  606    ].
  607prolog_message(ignored_weak_import(Into, From:PI)) -->
  608    [ 'Local definition of ~p overrides weak import from ~q'-
  609      [Into:PI, From]
  610    ].
  611prolog_message(undefined_export(Module, PI)) -->
  612    [ 'Exported procedure ~q:~q is not defined'-[Module, PI] ].
  613prolog_message(no_exported_op(Module, Op)) -->
  614    [ 'Operator ~q:~q is not exported (still defined)'-[Module, Op] ].
  615prolog_message(discontiguous((-)/2,_)) -->
  616    prolog_message(minus_in_identifier).
  617prolog_message(discontiguous(Proc,Current)) -->
  618    [ 'Clauses of ~p are not together in the source-file'-[Proc], nl ],
  619    current_definition(Proc, '  Earlier definition at '),
  620    [ '  Current predicate: ~p'-[Current], nl,
  621      '  Use :- discontiguous ~p. to suppress this message'-[Proc]
  622    ].
  623prolog_message(decl_no_effect(Goal)) -->
  624    [ 'Deprecated declaration has no effect: ~p'-[Goal] ].
  625prolog_message(load_file(start(Level, File))) -->
  626    [ '~|~t~*+Loading '-[Level] ],
  627    load_file(File),
  628    [ ' ...' ].
  629prolog_message(include_file(start(Level, File))) -->
  630    [ '~|~t~*+include '-[Level] ],
  631    load_file(File),
  632    [ ' ...' ].
  633prolog_message(include_file(done(Level, File))) -->
  634    [ '~|~t~*+included '-[Level] ],
  635    load_file(File).
  636prolog_message(load_file(done(Level, File, Action, Module, Time, Clauses))) -->
  637    [ '~|~t~*+'-[Level] ],
  638    load_file(File),
  639    [ ' ~w'-[Action] ],
  640    load_module(Module),
  641    [ ' ~2f sec, ~D clauses'-[Time, Clauses] ].
  642prolog_message(dwim_undefined(Goal, Alternatives)) -->
  643    { goal_to_predicate_indicator(Goal, Pred)
  644    },
  645    [ 'Undefined procedure: ~q'-[Pred], nl,
  646      '    However, there are definitions for:', nl
  647    ],
  648    dwim_message(Alternatives).
  649prolog_message(dwim_correct(Into)) -->
  650    [ 'Correct to: ~q? '-[Into], flush ].
  651prolog_message(error(loop_error(Spec), file_search(Used))) -->
  652    [ 'File search: too many levels of indirections on: ~p'-[Spec], nl,
  653      '    Used alias expansions:', nl
  654    ],
  655    used_search(Used).
  656prolog_message(minus_in_identifier) -->
  657    [ 'The "-" character should not be used to seperate words in an', nl,
  658      'identifier.  Check the SWI-Prolog FAQ for details.'
  659    ].
  660prolog_message(qlf(removed_after_error(File))) -->
  661    [ 'Removed incomplete QLF file ~w'-[File] ].
  662prolog_message(qlf(recompile(Spec,_Pl,_Qlf,Reason))) -->
  663    [ '~p: recompiling QLF file'-[Spec] ],
  664    qlf_recompile_reason(Reason).
  665prolog_message(qlf(can_not_recompile(Spec,QlfFile,_Reason))) -->
  666    [ '~p: can not recompile "~w" (access denied)'-[Spec, QlfFile], nl,
  667      '\tLoading from source'-[]
  668    ].
  669prolog_message(redefine_module(Module, OldFile, File)) -->
  670    [ 'Module "~q" already loaded from ~w.'-[Module, OldFile], nl,
  671      'Wipe and reload from ~w? '-[File], flush
  672    ].
  673prolog_message(redefine_module_reply) -->
  674    [ 'Please answer y(es), n(o) or a(bort)' ].
  675prolog_message(reloaded_in_module(Absolute, OldContext, LM)) -->
  676    [ '~w was previously loaded in module ~w'-[Absolute, OldContext], nl,
  677      '\tnow it is reloaded into module ~w'-[LM] ].
  678prolog_message(expected_layout(Expected, Pos)) -->
  679    [ 'Layout data: expected ~w, found: ~p'-[Expected, Pos] ].
  680
  681defined_definition(Message, Spec) -->
  682    { strip_module(user:Spec, M, Name/Arity),
  683      functor(Head, Name, Arity),
  684      predicate_property(M:Head, file(File)),
  685      predicate_property(M:Head, line_count(Line))
  686    },
  687    !,
  688    [ nl, '~w at ~w:~d'-[Message, File,Line] ].
  689defined_definition(_, _) --> [].
  690
  691used_search([]) -->
  692    [].
  693used_search([Alias=Expanded|T]) -->
  694    [ '        file_search_path(~p, ~p)'-[Alias, Expanded], nl ],
  695    used_search(T).
  696
  697load_file(file(Spec, _Path)) -->
  698    (   {atomic(Spec)}
  699    ->  [ '~w'-[Spec] ]
  700    ;   [ '~p'-[Spec] ]
  701    ).
  702%load_file(file(_, Path)) -->
  703%       [ '~w'-[Path] ].
  704
  705load_module(user) --> !.
  706load_module(system) --> !.
  707load_module(Module) -->
  708    [ ' into ~w'-[Module] ].
  709
  710goal_to_predicate_indicator(Goal, PI) :-
  711    strip_module(Goal, Module, Head),
  712    callable_name_arity(Head, Name, Arity),
  713    user_predicate_indicator(Module:Name/Arity, PI).
  714
  715callable_name_arity(Goal, Name, Arity) :-
  716    compound(Goal),
  717    !,
  718    compound_name_arity(Goal, Name, Arity).
  719callable_name_arity(Goal, Goal, 0) :-
  720    atom(Goal).
  721
  722user_predicate_indicator(Module:PI, PI) :-
  723    hidden_module(Module),
  724    !.
  725user_predicate_indicator(PI, PI).
  726
  727hidden_module(user) :- !.
  728hidden_module(system) :- !.
  729hidden_module(M) :-
  730    sub_atom(M, 0, _, _, $).
  731
  732current_definition(Proc, Prefix) -->
  733    { pi_head(Proc, Head),
  734      predicate_property(Head, file(File)),
  735      predicate_property(Head, line_count(Line))
  736    },
  737    [ '~w'-[Prefix], '~w:~d'-[File,Line], nl ].
  738current_definition(_, _) --> [].
  739
  740pi_head(Module:Name/Arity, Module:Head) :-
  741    !,
  742    atom(Module), atom(Name), integer(Arity),
  743    functor(Head, Name, Arity).
  744pi_head(Name/Arity, user:Head) :-
  745    atom(Name), integer(Arity),
  746    functor(Head, Name, Arity).
  747
  748qlf_recompile_reason(old) -->
  749    !,
  750    [ ' (out of date)'-[] ].
  751qlf_recompile_reason(_) -->
  752    [ ' (incompatible with current Prolog version)'-[] ].
  753
  754prolog_message(file_search(cache(Spec, _Cond), Path)) -->
  755    [ 'File search: ~p --> ~p (cache)'-[Spec, Path] ].
  756prolog_message(file_search(found(Spec, Cond), Path)) -->
  757    [ 'File search: ~p --> ~p OK ~p'-[Spec, Path, Cond] ].
  758prolog_message(file_search(tried(Spec, Cond), Path)) -->
  759    [ 'File search: ~p --> ~p NO ~p'-[Spec, Path, Cond] ].
  760
  761                 /*******************************
  762                 *              GC              *
  763                 *******************************/
  764
  765prolog_message(agc(start)) -->
  766    thread_context,
  767    [ 'AGC: ', flush ].
  768prolog_message(agc(done(Collected, Remaining, Time))) -->
  769    [ at_same_line,
  770      'reclaimed ~D atoms in ~3f sec. (remaining: ~D)'-
  771      [Collected, Time, Remaining]
  772    ].
  773prolog_message(cgc(start)) -->
  774    thread_context,
  775    [ 'CGC: ', flush ].
  776prolog_message(cgc(done(CollectedClauses, _CollectedBytes,
  777                        RemainingBytes, Time))) -->
  778    [ at_same_line,
  779      'reclaimed ~D clauses in ~3f sec. (pending: ~D bytes)'-
  780      [CollectedClauses, Time, RemainingBytes]
  781    ].
  782
  783		 /*******************************
  784		 *        STACK OVERFLOW	*
  785		 *******************************/
  786
  787out_of_stack(Context) -->
  788    { human_stack_size(Context.localused,   Local),
  789      human_stack_size(Context.globalused,  Global),
  790      human_stack_size(Context.trailused,   Trail),
  791      human_stack_size(Context.stack_limit, Limit),
  792      LCO is (100*(Context.depth - Context.environments))/Context.depth
  793    },
  794    [ 'Stack limit (~s) exceeded'-[Limit], nl,
  795      '  Stack sizes: local: ~s, global: ~s, trail: ~s'-[Local,Global,Trail], nl,
  796      '  Stack depth: ~D, last-call: ~0f%, Choice points: ~D'-
  797         [Context.depth, LCO, Context.choicepoints], nl
  798    ],
  799    overflow_reason(Context, Resolve),
  800    resolve_overflow(Resolve).
  801
  802human_stack_size(Size, String) :-
  803    Size < 100,
  804    format(string(String), '~dKb', [Size]).
  805human_stack_size(Size, String) :-
  806    Size < 100 000,
  807    Value is Size / 1024,
  808    format(string(String), '~1fMb', [Value]).
  809human_stack_size(Size, String) :-
  810    Value is Size / (1024*1024),
  811    format(string(String), '~1fGb', [Value]).
  812
  813overflow_reason(Context, fix) -->
  814    show_non_termination(Context),
  815    !.
  816overflow_reason(Context, enlarge) -->
  817    { Stack = Context.get(stack) },
  818    !,
  819    [ '  In:'-[], nl ],
  820    stack(Stack).
  821overflow_reason(_Context, enlarge) -->
  822    [ '  Insufficient global stack'-[] ].
  823
  824show_non_termination(Context) -->
  825    (   { Stack = Context.get(cycle) }
  826    ->  [ '  Probable infinite recursion (cycle):'-[], nl ]
  827    ;   { Stack = Context.get(non_terminating) }
  828    ->  [ '  Possible non-terminating recursion:'-[], nl ]
  829    ),
  830    stack(Stack).
  831
  832stack([]) --> [].
  833stack([frame(Depth, M:Goal, _)|T]) -->
  834    [ '    [~D] ~q:'-[Depth, M] ],
  835    stack_goal(Goal),
  836    [ nl ],
  837    stack(T).
  838
  839stack_goal(Goal) -->
  840    { compound(Goal),
  841      !,
  842      compound_name_arity(Goal, Name, Arity)
  843    },
  844    [ '~q('-[Name] ],
  845    stack_goal_args(1, Arity, Goal),
  846    [ ')'-[] ].
  847stack_goal(Goal) -->
  848    [ '~q'-[Goal] ].
  849
  850stack_goal_args(I, Arity, Goal) -->
  851    { I =< Arity,
  852      !,
  853      arg(I, Goal, A),
  854      I2 is I + 1
  855    },
  856    stack_goal_arg(A),
  857    (   { I2 =< Arity }
  858    ->  [ ', '-[] ],
  859        stack_goal_args(I2, Arity, Goal)
  860    ;   []
  861    ).
  862stack_goal_args(_, _, _) -->
  863    [].
  864
  865stack_goal_arg(A) -->
  866    { nonvar(A),
  867      A = [Len|T],
  868      !
  869    },
  870    (   {Len == cyclic_term}
  871    ->  [ '[cyclic list]'-[] ]
  872    ;   {T == []}
  873    ->  [ '[length:~D]'-[Len] ]
  874    ;   [ '[length:~D|~p]'-[Len, T] ]
  875    ).
  876stack_goal_arg(A) -->
  877    { nonvar(A),
  878      A = _/_,
  879      !
  880    },
  881    [ '<compound ~p>'-[A] ].
  882stack_goal_arg(A) -->
  883    [ '~p'-[A] ].
  884
  885resolve_overflow(fix) -->
  886    [].
  887resolve_overflow(enlarge) -->
  888    { current_prolog_flag(stack_limit, LimitBytes),
  889      NewLimit is LimitBytes * 2
  890    },
  891    [ nl,
  892      'Use the --stack_limit=size[KMG] command line option or'-[], nl,
  893      '?- set_prolog_flag(stack_limit, ~I). to double the limit.'-[NewLimit]
  894    ].
  895
  896
  897                 /*******************************
  898                 *        MAKE/AUTOLOAD         *
  899                 *******************************/
  900
  901prolog_message(make(reload(Files))) -->
  902    { length(Files, N)
  903    },
  904    [ 'Make: reloading ~D files'-[N] ].
  905prolog_message(make(done(_Files))) -->
  906    [ 'Make: finished' ].
  907prolog_message(make(library_index(Dir))) -->
  908    [ 'Updating index for library ~w'-[Dir] ].
  909prolog_message(autoload(Pred, File)) -->
  910    thread_context,
  911    [ 'autoloading ~p from ~w'-[Pred, File] ].
  912prolog_message(autoload(read_index(Dir))) -->
  913    [ 'Loading autoload index for ~w'-[Dir] ].
  914
  915
  916                 /*******************************
  917                 *       COMPILER WARNINGS      *
  918                 *******************************/
  919
  920% print warnings about dubious code raised by the compiler.
  921% TBD: pass in PC to produce exact error locations.
  922
  923prolog_message(compiler_warnings(Clause, Warnings0)) -->
  924    {   print_goal_options(DefOptions),
  925        (   prolog_load_context(variable_names, VarNames)
  926        ->  warnings_with_named_vars(Warnings0, VarNames, Warnings),
  927            Options = [variable_names(VarNames)|DefOptions]
  928        ;   Options = DefOptions,
  929            Warnings = Warnings0
  930        )
  931    },
  932    compiler_warnings(Warnings, Clause, Options).
  933
  934warnings_with_named_vars([], _, []).
  935warnings_with_named_vars([H|T0], VarNames, [H|T]) :-
  936    term_variables(H, Vars),
  937    '$member'(V1, Vars),
  938    '$member'(_=V2, VarNames),
  939    V1 == V2,
  940    !,
  941    warnings_with_named_vars(T0, VarNames, T).
  942warnings_with_named_vars([_|T0], VarNames, T) :-
  943    warnings_with_named_vars(T0, VarNames, T).
  944
  945
  946compiler_warnings([], _, _) --> [].
  947compiler_warnings([H|T], Clause, Options) -->
  948    (   compiler_warning(H, Clause, Options)
  949    ->  []
  950    ;   [ 'Unknown compiler warning: ~W'-[H,Options] ]
  951    ),
  952    (   {T==[]}
  953    ->  []
  954    ;   [nl]
  955    ),
  956    compiler_warnings(T, Clause, Options).
  957
  958compiler_warning(eq_vv(A,B), _Clause, Options) -->
  959    (   { A == B }
  960    ->  [ 'Test is always true: ~W'-[A==B, Options] ]
  961    ;   [ 'Test is always false: ~W'-[A==B, Options] ]
  962    ).
  963compiler_warning(eq_singleton(A,B), _Clause, Options) -->
  964    [ 'Test is always false: ~W'-[A==B, Options] ].
  965compiler_warning(neq_vv(A,B), _Clause, Options) -->
  966    (   { A \== B }
  967    ->  [ 'Test is always true: ~W'-[A\==B, Options] ]
  968    ;   [ 'Test is always false: ~W'-[A\==B, Options] ]
  969    ).
  970compiler_warning(neq_singleton(A,B), _Clause, Options) -->
  971    [ 'Test is always true: ~W'-[A\==B, Options] ].
  972compiler_warning(unify_singleton(A,B), _Clause, Options) -->
  973    [ 'Unified variable is not used: ~W'-[A=B, Options] ].
  974compiler_warning(always(Bool, Pred, Arg), _Clause, Options) -->
  975    { Goal =.. [Pred,Arg] },
  976    [ 'Test is always ~w: ~W'-[Bool, Goal, Options] ].
  977compiler_warning(unbalanced_var(V), _Clause, Options) -->
  978    [ 'Variable not introduced in all branches: ~W'-[V, Options] ].
  979compiler_warning(branch_singleton(V), _Clause, Options) -->
  980    [ 'Singleton variable in branch: ~W'-[V, Options] ].
  981compiler_warning(negation_singleton(V), _Clause, Options) -->
  982    [ 'Singleton variable in \\+: ~W'-[V, Options] ].
  983compiler_warning(multiton(V), _Clause, Options) -->
  984    [ 'Singleton-marked variable appears more than once: ~W'-[V, Options] ].
  985
  986print_goal_options(
  987    [ quoted(true),
  988      portray(true)
  989    ]).
  990
  991
  992                 /*******************************
  993                 *      TOPLEVEL MESSAGES       *
  994                 *******************************/
  995
  996prolog_message(version) -->
  997    { current_prolog_flag(version_git, Version) },
  998    !,
  999    [ '~w'-[Version] ].
 1000prolog_message(version) -->
 1001    { current_prolog_flag(version_data, swi(Major,Minor,Patch,Options))
 1002    },
 1003    (   { memberchk(tag(Tag), Options) }
 1004    ->  [ '~w.~w.~w-~w'-[Major, Minor, Patch, Tag] ]
 1005    ;   [ '~w.~w.~w'-[Major, Minor, Patch] ]
 1006    ).
 1007prolog_message(address_bits) -->
 1008    { current_prolog_flag(address_bits, Bits)
 1009    },
 1010    !,
 1011    [ '~d bits, '-[Bits] ].
 1012prolog_message(threads) -->
 1013    { current_prolog_flag(threads, true)
 1014    },
 1015    !,
 1016    [ 'threaded, ' ].
 1017prolog_message(threads) -->
 1018    [].
 1019prolog_message(copyright) -->
 1020    [ 'SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software.', nl,
 1021      'Please run ?- license. for legal details.'
 1022    ].
 1023prolog_message(user_versions) -->
 1024    (   { findall(Msg, prolog:version_msg(Msg), Msgs),
 1025          Msgs \== []
 1026        }
 1027    ->  [nl],
 1028        user_version_messages(Msgs)
 1029    ;   []
 1030    ).
 1031prolog_message(documentaton) -->
 1032    [ 'For online help and background, visit http://www.swi-prolog.org', nl,
 1033      'For built-in help, use ?- help(Topic). or ?- apropos(Word).'
 1034    ].
 1035prolog_message(welcome) -->
 1036    [ 'Welcome to SWI-Prolog (' ],
 1037    prolog_message(threads),
 1038    prolog_message(address_bits),
 1039    ['version ' ],
 1040    prolog_message(version),
 1041    [ ')', nl ],
 1042    prolog_message(copyright),
 1043    [ nl ],
 1044    prolog_message(user_versions),
 1045    [ nl ],
 1046    prolog_message(documentaton),
 1047    [ nl, nl ].
 1048prolog_message(about) -->
 1049    [ 'SWI-Prolog version (' ],
 1050    prolog_message(threads),
 1051    prolog_message(address_bits),
 1052    ['version ' ],
 1053    prolog_message(version),
 1054    [ ')', nl ],
 1055    prolog_message(copyright).
 1056prolog_message(halt) -->
 1057    [ 'halt' ].
 1058prolog_message(break(begin, Level)) -->
 1059    [ 'Break level ~d'-[Level] ].
 1060prolog_message(break(end, Level)) -->
 1061    [ 'Exit break level ~d'-[Level] ].
 1062prolog_message(var_query(_)) -->
 1063    [ '... 1,000,000 ............ 10,000,000 years later', nl, nl,
 1064      '~t~8|>> 42 << (last release gives the question)'
 1065    ].
 1066prolog_message(close_on_abort(Stream)) -->
 1067    [ 'Abort: closed stream ~p'-[Stream] ].
 1068prolog_message(cancel_halt(Reason)) -->
 1069    [ 'Halt cancelled: ~p'-[Reason] ].
 1070
 1071prolog_message(query(QueryResult)) -->
 1072    query_result(QueryResult).
 1073
 1074query_result(no) -->            % failure
 1075    [ ansi([bold,fg(red)], 'false.', []) ],
 1076    extra_line.
 1077query_result(yes([])) -->      % prompt_alternatives_on: groundness
 1078    !,
 1079    [ ansi(bold, 'true.', []) ],
 1080    extra_line.
 1081query_result(yes(Residuals)) -->
 1082    result([], Residuals),
 1083    extra_line.
 1084query_result(done) -->          % user typed <CR>
 1085    extra_line.
 1086query_result(yes(Bindings, Residuals)) -->
 1087    result(Bindings, Residuals),
 1088    prompt(yes, Bindings, Residuals).
 1089query_result(more(Bindings, Residuals)) -->
 1090    result(Bindings, Residuals),
 1091    prompt(more, Bindings, Residuals).
 1092query_result(help) -->
 1093    [ nl, 'Actions:'-[], nl, nl,
 1094      '; (n, r, space, TAB): redo    t:          trace & redo'-[], nl,
 1095      'b:                    break   c (a, RET): exit'-[], nl,
 1096      'w:                    write   p           print'-[], nl,
 1097      'h (?):                help'-[],
 1098      nl, nl
 1099    ].
 1100query_result(action) -->
 1101    [ 'Action? '-[], flush ].
 1102query_result(confirm) -->
 1103    [ 'Please answer \'y\' or \'n\'? '-[], flush ].
 1104query_result(eof) -->
 1105    [ nl ].
 1106query_result(toplevel_open_line) -->
 1107    [].
 1108
 1109prompt(Answer, [], []-[]) -->
 1110    !,
 1111    prompt(Answer, empty).
 1112prompt(Answer, _, _) -->
 1113    !,
 1114    prompt(Answer, non_empty).
 1115
 1116prompt(yes, empty) -->
 1117    !,
 1118    [ ansi(bold, 'true.', []) ],
 1119    extra_line.
 1120prompt(yes, _) -->
 1121    !,
 1122    [ full_stop ],
 1123    extra_line.
 1124prompt(more, empty) -->
 1125    !,
 1126    [ ansi(bold, 'true ', []), flush ].
 1127prompt(more, _) -->
 1128    !,
 1129    [ ' '-[], flush ].
 1130
 1131result(Bindings, Residuals) -->
 1132    { current_prolog_flag(answer_write_options, Options0),
 1133      Options = [partial(true)|Options0]
 1134    },
 1135    bindings(Bindings, [priority(699)|Options]),
 1136    bind_res_sep(Bindings, Residuals),
 1137    residuals(Residuals, [priority(999)|Options]).
 1138
 1139bindings([], _) -->
 1140    [].
 1141bindings([binding(Names,Skel,Subst)|T], Options) -->
 1142    { '$last'(Names, Name) },
 1143    var_names(Names), value(Name, Skel, Subst, Options),
 1144    (   { T \== [] }
 1145    ->  [ ','-[], nl ],
 1146        bindings(T, Options)
 1147    ;   []
 1148    ).
 1149
 1150var_names([Name]) -->
 1151    !,
 1152    [ '~w = '-[Name] ].
 1153var_names([Name1,Name2|T]) -->
 1154    !,
 1155    [ '~w = ~w, '-[Name1, Name2] ],
 1156    var_names([Name2|T]).
 1157
 1158
 1159value(Name, Skel, Subst, Options) -->
 1160    (   { var(Skel), Subst = [Skel=S] }
 1161    ->  { Skel = '$VAR'(Name) },
 1162        [ '~W'-[S, Options] ]
 1163    ;   [ '~W'-[Skel, Options] ],
 1164        substitution(Subst, Options)
 1165    ).
 1166
 1167substitution([], _) --> !.
 1168substitution([N=V|T], Options) -->
 1169    [ ', ', ansi(fg(green), '% where', []), nl,
 1170      '    ~w = ~W'-[N,V,Options] ],
 1171    substitutions(T, Options).
 1172
 1173substitutions([], _) --> [].
 1174substitutions([N=V|T], Options) -->
 1175    [ ','-[], nl, '    ~w = ~W'-[N,V,Options] ],
 1176    substitutions(T, Options).
 1177
 1178
 1179residuals(Normal-Hidden, Options) -->
 1180    residuals1(Normal, Options),
 1181    bind_res_sep(Normal, Hidden),
 1182    (   {Hidden == []}
 1183    ->  []
 1184    ;   [ansi(fg(green), '% with pending residual goals', []), nl]
 1185    ),
 1186    residuals1(Hidden, Options).
 1187
 1188residuals1([], _) -->
 1189    [].
 1190residuals1([G|Gs], Options) -->
 1191    (   { Gs \== [] }
 1192    ->  [ '~W,'-[G, Options], nl ],
 1193        residuals1(Gs, Options)
 1194    ;   [ '~W'-[G, Options] ]
 1195    ).
 1196
 1197bind_res_sep(_, []) --> !.
 1198bind_res_sep(_, []-[]) --> !.
 1199bind_res_sep([], _) --> !.
 1200bind_res_sep(_, _) --> [','-[], nl].
 1201
 1202extra_line -->
 1203    { current_prolog_flag(toplevel_extra_white_line, true) },
 1204    !,
 1205    ['~N'-[]].
 1206extra_line -->
 1207    [].
 1208
 1209prolog_message(if_tty(Message)) -->
 1210    (   {current_prolog_flag(tty_control, true)}
 1211    ->  [ at_same_line | Message ]
 1212    ;   []
 1213    ).
 1214prolog_message(halt(Reason)) -->
 1215    [ '~w: halt'-[Reason] ].
 1216prolog_message(no_action(Char)) -->
 1217    [ 'Unknown action: ~c (h for help)'-[Char], nl ].
 1218
 1219prolog_message(history(help(Show, Help))) -->
 1220    [ 'History Commands:', nl,
 1221      '    !!.              Repeat last query', nl,
 1222      '    !nr.             Repeat query numbered <nr>', nl,
 1223      '    !str.            Repeat last query starting with <str>', nl,
 1224      '    !?str.           Repeat last query holding <str>', nl,
 1225      '    ^old^new.        Substitute <old> into <new> of last query', nl,
 1226      '    !nr^old^new.     Substitute in query numbered <nr>', nl,
 1227      '    !str^old^new.    Substitute in query starting with <str>', nl,
 1228      '    !?str^old^new.   Substitute in query holding <str>', nl,
 1229      '    ~w.~21|Show history list'-[Show], nl,
 1230      '    ~w.~21|Show this list'-[Help], nl, nl
 1231    ].
 1232prolog_message(history(no_event)) -->
 1233    [ '! No such event' ].
 1234prolog_message(history(bad_substitution)) -->
 1235    [ '! Bad substitution' ].
 1236prolog_message(history(expanded(Event))) -->
 1237    [ '~w.'-[Event] ].
 1238prolog_message(history(history(Events))) -->
 1239    history_events(Events).
 1240
 1241history_events([]) -->
 1242    [].
 1243history_events([Nr/Event|T]) -->
 1244    [ '~t~w   ~8|~W~W'-[ Nr,
 1245                         Event, [partial(true)],
 1246                         '.', [partial(true)]
 1247                       ],
 1248      nl
 1249    ],
 1250    history_events(T).
 1251
 1252
 1253user_version_messages([]) --> [].
 1254user_version_messages([H|T]) -->
 1255    user_version_message(H),
 1256    user_version_messages(T).

 user_version_message(+Term)

 1260user_version_message(Term) -->
 1261    translate_message2(Term), !, [nl].
 1262user_version_message(Atom) -->
 1263    [ '~w'-[Atom], nl ].
 1264
 1265
 1266                 /*******************************
 1267                 *       DEBUGGER MESSAGES      *
 1268                 *******************************/
 1269
 1270prolog_message(spy(Head)) -->
 1271    { goal_to_predicate_indicator(Head, Pred)
 1272    },
 1273    [ 'Spy point on ~p'-[Pred] ].
 1274prolog_message(nospy(Head)) -->
 1275    { goal_to_predicate_indicator(Head, Pred)
 1276    },
 1277    [ 'Spy point removed from ~p'-[Pred] ].
 1278prolog_message(trace_mode(Bool)) -->
 1279    [ 'Trace mode switched to ~w'-[Bool] ].
 1280prolog_message(debug_mode(Bool)) -->
 1281    [ 'Debug mode switched to ~w'-[Bool] ].
 1282prolog_message(debugging(Bool)) -->
 1283    [ 'Debug mode is ~w'-[Bool] ].
 1284prolog_message(spying([])) -->
 1285    !,
 1286    [ 'No spy points' ].
 1287prolog_message(spying(Heads)) -->
 1288    [ 'Spy points (see spy/1) on:', nl ],
 1289    predicate_list(Heads).
 1290prolog_message(trace(Head, [])) -->
 1291    !,
 1292    { goal_to_predicate_indicator(Head, Pred)
 1293    },
 1294    [ '        ~p: Not tracing'-[Pred], nl].
 1295prolog_message(trace(Head, Ports)) -->
 1296    { goal_to_predicate_indicator(Head, Pred)
 1297    },
 1298    [ '        ~p: ~w'-[Pred, Ports], nl].
 1299prolog_message(tracing([])) -->
 1300    !,
 1301    [ 'No traced predicates (see trace/1)' ].
 1302prolog_message(tracing(Heads)) -->
 1303    [ 'Trace points (see trace/1) on:', nl ],
 1304    tracing_list(Heads).
 1305
 1306predicate_list([]) -->                  % TBD: Share with dwim, etc.
 1307    [].
 1308predicate_list([H|T]) -->
 1309    { goal_to_predicate_indicator(H, Pred)
 1310    },
 1311    [ '        ~p'-[Pred], nl],
 1312    predicate_list(T).
 1313
 1314tracing_list([]) -->
 1315    [].
 1316tracing_list([trace(Head, Ports)|T]) -->
 1317    translate_message(trace(Head, Ports)),
 1318    tracing_list(T).
 1319
 1320prolog_message(frame(Frame, backtrace, _PC)) -->
 1321    !,
 1322    { prolog_frame_attribute(Frame, level, Level)
 1323    },
 1324    [ ansi(bold, '~t[~D] ~10|', [Level]) ],
 1325    frame_context(Frame),
 1326    frame_goal(Frame).
 1327prolog_message(frame(Frame, choice, PC)) -->
 1328    !,
 1329    prolog_message(frame(Frame, backtrace, PC)).
 1330prolog_message(frame(_, cut_call, _)) --> !, [].
 1331prolog_message(frame(Frame, trace(Port), _PC)) -->
 1332    !,
 1333    [ ' T ' ],
 1334    port(Port),
 1335    frame_level(Frame),
 1336    frame_context(Frame),
 1337    frame_goal(Frame).
 1338prolog_message(frame(Frame, Port, _PC)) -->
 1339    frame_flags(Frame),
 1340    port(Port),
 1341    frame_level(Frame),
 1342    frame_context(Frame),
 1343    frame_depth_limit(Port, Frame),
 1344    frame_goal(Frame),
 1345    [ flush ].
 1346
 1347frame_goal(Frame) -->
 1348    { prolog_frame_attribute(Frame, goal, Goal0),
 1349      clean_goal(Goal0, Goal),
 1350      current_prolog_flag(debugger_write_options, Options)
 1351    },
 1352    [ '~W'-[Goal, Options] ].
 1353
 1354frame_level(Frame) -->
 1355    { prolog_frame_attribute(Frame, level, Level)
 1356    },
 1357    [ '(~D) '-[Level] ].
 1358
 1359frame_context(Frame) -->
 1360    (   { current_prolog_flag(debugger_show_context, true),
 1361          prolog_frame_attribute(Frame, context_module, Context)
 1362        }
 1363    ->  [ '[~w] '-[Context] ]
 1364    ;   []
 1365    ).
 1366
 1367frame_depth_limit(fail, Frame) -->
 1368    { prolog_frame_attribute(Frame, depth_limit_exceeded, true)
 1369    },
 1370    !,
 1371    [ '[depth-limit exceeded] ' ].
 1372frame_depth_limit(_, _) -->
 1373    [].
 1374
 1375frame_flags(Frame) -->
 1376    { prolog_frame_attribute(Frame, goal, Goal),
 1377      (   predicate_property(Goal, transparent)
 1378      ->  T = '^'
 1379      ;   T = ' '
 1380      ),
 1381      (   predicate_property(Goal, spying)
 1382      ->  S = '*'
 1383      ;   S = ' '
 1384      )
 1385    },
 1386    [ '~w~w '-[T, S] ].
 1387
 1388port(Port) -->
 1389    { port_name(Port, Colour, Name)
 1390    },
 1391    !,
 1392    [ ansi([bold,fg(Colour)], '~w: ', [Name]) ].
 1393
 1394port_name(call,      green,   'Call').
 1395port_name(exit,      green,   'Exit').
 1396port_name(fail,      red,     'Fail').
 1397port_name(redo,      yellow,  'Redo').
 1398port_name(unify,     blue,    'Unify').
 1399port_name(exception, magenta, 'Exception').
 1400
 1401clean_goal(M:Goal, Goal) :-
 1402    hidden_module(M),
 1403    !.
 1404clean_goal(M:Goal, Goal) :-
 1405    predicate_property(M:Goal, built_in),
 1406    !.
 1407clean_goal(Goal, Goal).
 1408
 1409
 1410                 /*******************************
 1411                 *        COMPATIBILITY         *
 1412                 *******************************/
 1413
 1414prolog_message(compatibility(renamed(Old, New))) -->
 1415    [ 'The predicate ~p has been renamed to ~p.'-[Old, New], nl,
 1416      'Please update your sources for compatibility with future versions.'
 1417    ].
 1418
 1419
 1420                 /*******************************
 1421                 *            THREADS           *
 1422                 *******************************/
 1423
 1424prolog_message(abnormal_thread_completion(Goal, exception(Ex))) -->
 1425    !,
 1426    [ 'Thread running "~p" died on exception: '-[Goal] ],
 1427    translate_message(Ex).
 1428prolog_message(abnormal_thread_completion(Goal, fail)) -->
 1429    [ 'Thread running "~p" died due to failure'-[Goal] ].
 1430prolog_message(threads_not_died(Running)) -->
 1431    [ 'The following threads wouldn\'t die: ~p'-[Running] ].
 1432
 1433
 1434                 /*******************************
 1435                 *             PACKS            *
 1436                 *******************************/
 1437
 1438prolog_message(pack(attached(Pack, BaseDir))) -->
 1439    [ 'Attached package ~w at ~q'-[Pack, BaseDir] ].
 1440prolog_message(pack(duplicate(Entry, OldDir, Dir))) -->
 1441    [ 'Package ~w already attached at ~q.'-[Entry,OldDir], nl,
 1442      '\tIgnoring version from ~q'- [Entry, OldDir, Dir]
 1443    ].
 1444prolog_message(pack(no_arch(Entry, Arch))) -->
 1445    [ 'Package ~w: no binary for architecture ~w'-[Entry, Arch] ].
 1446
 1447                 /*******************************
 1448                 *             MISC             *
 1449                 *******************************/
 1450
 1451prolog_message(null_byte_in_path(Component)) -->
 1452    [ '0-byte in PATH component: ~p (skipped directory)'-[Component] ].
 1453prolog_message(invalid_tmp_dir(Dir, Reason)) -->
 1454    [ 'Cannot use ~p as temporary file directory: ~w'-[Dir, Reason] ].
 1455prolog_message(ambiguous_stream_pair(Pair)) -->
 1456    [ 'Ambiguous operation on stream pair ~p'-[Pair] ].
 1457
 1458env(Name) -->
 1459    { current_prolog_flag(windows, true) },
 1460    [ '%~w%'-[Name] ].
 1461env(Name) -->
 1462    [ '$~w'-[Name] ].
 1463
 1464		 /*******************************
 1465		 *          DEPRECATED		*
 1466		 *******************************/
 1467
 1468deprecated(set_prolog_stack(_Stack,limit)) -->
 1469    [ 'set_prolog_stack/2: limit(Size) sets the combined limit.'-[], nl,
 1470      'See http://www.swi-prolog.org/changes/stack-limit.html'
 1471    ].
 1472
 1473
 1474                 /*******************************
 1475                 *      PRINTING MESSAGES       *
 1476                 *******************************/
 1477
 1478:- multifile
 1479    user:message_hook/3,
 1480    prolog:message_prefix_hook/2. 1481:- dynamic
 1482    user:message_hook/3,
 1483    prolog:message_prefix_hook/2. 1484:- thread_local
 1485    user:thread_message_hook/3.