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)  1985-2025, University of Amsterdam
    7                              VU University Amsterdam
    8                              SWI-Prolog Solutions b.v.
    9    All rights reserved.
   10
   11    Redistribution and use in source and binary forms, with or without
   12    modification, are permitted provided that the following conditions
   13    are met:
   14
   15    1. Redistributions of source code must retain the above copyright
   16       notice, this list of conditions and the following disclaimer.
   17
   18    2. Redistributions in binary form must reproduce the above copyright
   19       notice, this list of conditions and the following disclaimer in
   20       the documentation and/or other materials provided with the
   21       distribution.
   22
   23    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   24    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   25    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   26    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   27    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   28    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   29    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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   31    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   32    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   33    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   34    POSSIBILITY OF SUCH DAMAGE.
   35*/
   36
   37:- module(quintus,
   38        [ unix/1,
   39%         file_exists/1,
   40
   41          abs/2,
   42          sin/2,
   43          cos/2,
   44          tan/2,
   45          log/2,
   46          log10/2,
   47          pow/3,
   48          ceiling/2,
   49          floor/2,
   50          round/2,
   51          acos/2,
   52          asin/2,
   53          atan/2,
   54          atan2/3,
   55          sign/2,
   56          sqrt/2,
   57
   58          genarg/3,
   59
   60          no_style_check/1,
   61          otherwise/0,
   62          simple/1,
   63%         statistics/2,                 % Please access as quintus:statistics/2
   64          prolog_flag/2,
   65
   66          date/1,                       % -date(Year, Month, Day)
   67
   68          current_stream/3,             % ?File, ?Mode, ?Stream
   69          stream_position/3,            % +Stream, -Old, +New
   70          skip_line/0,
   71          skip_line/1,                  % +Stream
   72
   73          compile/1,                    % +File(s)
   74
   75          atom_char/2,
   76          midstring/3,                  % ABC, B, AC
   77          midstring/4,                  % ABC, B, AC, LenA
   78          midstring/5,                  % ABC, B, AC, LenA, LenB
   79          midstring/6,                  % ABC, B, AC, LenA, LenB, LenC
   80
   81          raise_exception/1,            % +Exception
   82          on_exception/3                % +Ball, :Goal, :Recover
   83        ]).   84:- autoload(library(apply),[maplist/3]).   85:- autoload(library(date),[date_time_value/3]).   86:- autoload(library(shell),[shell/0]).

  105                /********************************
  106                *      SYSTEM INTERACTION       *
  107                *********************************/

 unix(+Action)

This predicate provides a partial emulation of the corresponding Quintus predicate. It provides access to some operating system features and unlike the name suggests, is not operating system specific. Defined actions are below.

system(+Command)

Equivalent to shell(Command)

shell(+Command)

Equivalent to shell(Command)

access(File,0)

Equivalent to access_file(File, read)

cd(Dir)

Equivalent to working_directory(_, Dir)

args(List)

Equivalent to current_prolog_flag(os_argv, List).

argv(List)

Equivalent to args(List), but arguments that are syntactically valid numbers are passed as a number.

  130unix(system(Command)) :-
  131    shell(Command).
  132unix(shell(Command)) :-
  133    shell(Command).
  134unix(shell) :-
  135    shell.
  136unix(access(File, 0)) :-
  137    access_file(File, read).
  138unix(cd) :-
  139    expand_file_name(~, [Home]),
  140    working_directory(_, Home).
  141unix(cd(Dir)) :-
  142    working_directory(_, Dir).
  143unix(args(L)) :-
  144    current_prolog_flag(os_argv, L).
  145unix(argv(L)) :-
  146    current_prolog_flag(os_argv, S),
  147    maplist(to_prolog, S, L).
  148
  149to_prolog(S, A) :-
  150    name(S, L),
  151    name(A, L).
  152
  153
  154                /********************************
  155                *        META PREDICATES        *
  156                *********************************/

 otherwise

For (A -> B ; otherwise -> C)

  162otherwise.
  163
  164
  165                /********************************
  166                *          ARITHMETIC           *
  167                *********************************/

 abs(+Number, -Absolute)

Unify `Absolute' with the absolute value of `Number'.

  172abs(Number, Absolute) :-
  173    Absolute is abs(Number).

 sin(+Angle, -Sine) is det

 cos(+Angle, -Cosine) is det

 tan(+Angle, -Tangent) is det

 log(+X, -NatLog) is det

 log10(+X, -Log) is det

 pow(+X, +Y, -Pow) is det

 ceiling(+X, -Value) is det

 floor(+X, -Value) is det

 round(+X, -Value) is det

 sqrt(+X, -Value) is det

 acos(+X, -Value) is det

 asin(+X, -Value) is det

 atan(+X, -Value) is det

 atan2(+Y, +X, -Value) is det

 sign(+X, -Value) is det

Math library predicates. SWI-Prolog (and ISO) support these as functions under is/2, etc.

deprecated

- Do not use these predicates except for compatibility reasons.

Compatibility

- Quintus Prolog.

  198sin(A, V) :-      V is sin(A).
  199cos(A, V) :-      V is cos(A).
  200tan(A, V) :-      V is tan(A).
  201log(A, V) :-      V is log(A).
  202log10(X, V) :-    V is log10(X).
  203pow(X,Y,V) :-     V is X**Y.
  204ceiling(X, V) :-  V is ceil(X).
  205floor(X, V) :-    V is floor(X).
  206round(X, V) :-    V is round(X).
  207sqrt(X, V) :-     V is sqrt(X).
  208acos(X, V) :-     V is acos(X).
  209asin(X, V) :-     V is asin(X).
  210atan(X, V) :-     V is atan(X).
  211atan2(Y, X, V) :- V is atan(Y, X).
  212sign(X, V) :-     V is sign(X).
  213
  214
  215                 /*******************************
  216                 *      TERM MANIPULATION       *
  217                 *******************************/

 genarg(?Index, +Term, ?Arg) is nondet

Generalised version of ISO arg/3. SWI-Prolog's arg/3 is already genarg/3.

  224genarg(N, T, A) :-
  225    arg(N, T, A).
  226
  227
  228                 /*******************************
  229                 *            FLAGS             *
  230                 *******************************/

 prolog_flag(?Flag, ?Value) is nondet

Same as ISO current_prolog_flag/2. Maps version.

bug

- Should map relevant Quintus flag identifiers.

  238prolog_flag(version, Version) :-
  239    !,
  240    current_prolog_flag(version_data, swi(Major, Minor, Patch, _)),
  241    current_prolog_flag(arch, Arch),
  242    current_prolog_flag(compiled_at, Compiled),
  243    atomic_list_concat(['SWI-Prolog ',
  244                 Major, '.', Minor, '.', Patch,
  245                 ' (', Arch, '): ', Compiled], Version).
  246prolog_flag(Flag, Value) :-
  247    current_prolog_flag(Flag, Value).
  248
  249
  250                 /*******************************
  251                 *          STATISTICS          *
  252                 *******************************/
  253
  254%       Here used to be a definition of Quintus statistics/2 in traditional
  255%       SWI-Prolog statistics/2.  The current built-in emulates Quintus
  256%       almost completely.
  257
  258
  259                 /*******************************
  260                 *           DATE/TIME          *
  261                 *******************************/

 date(-Date) is det

Get current date as date(Y,M,D)

  267date(Date) :-
  268    get_time(T),
  269    stamp_date_time(T, DaTime, local),
  270    date_time_value(date, DaTime, Date).
  271
  272
  273                /********************************
  274                *          STYLE CHECK          *
  275                *********************************/

 no_style_check(Style) is det

Same as SWI-Prolog style_check(-Style). The Quintus option single_var is mapped to singleton.

See also

- style_check/1.

  284q_style_option(single_var, singleton) :- !.
  285q_style_option(Option, Option).
  286
  287no_style_check(QOption) :-
  288    q_style_option(QOption, SWIOption),
  289    style_check(-SWIOption).
  290
  291
  292                 /*******************************
  293                 *            TYPES             *
  294                 *******************************/

 simple(@Term) is semidet

Term is atomic or a variable.

  300simple(X) :-
  301    (   atomic(X)
  302    ->  true
  303    ;   var(X)
  304    ).
  305
  306
  307                 /*******************************
  308                 *            STREAMS           *
  309                 *******************************/

 current_stream(?Object, ?Mode, ?Stream)

SICStus/Quintus and backward compatible predicate. New code should be using the ISO compatible stream_property/2.

  316current_stream(Object, Mode, Stream) :-
  317    stream_property(Stream, mode(FullMode)),
  318    stream_mode(FullMode, Mode),
  319    (   stream_property(Stream, file_name(Object0))
  320    ->  true
  321    ;   stream_property(Stream, file_no(Object0))
  322    ->  true
  323    ;   Object0 = []
  324    ),
  325    Object = Object0.
  326
  327stream_mode(read,   read).
  328stream_mode(write,  write).
  329stream_mode(append, write).
  330stream_mode(update, write).

 stream_position(+Stream, -Old, +New)

True when Old is the current position in Stream and the stream has been repositioned to New.

deprecated

- New code should use the ISO predicates stream_property/2 and set_stream_position/2.

  340stream_position(Stream, Old, New) :-
  341    stream_property(Stream, position(Old)),
  342    set_stream_position(Stream, New).

 skip_line is det

 skip_line(Stream) is det

Skip the rest of the current line (on Stream). Same as skip(0'\n).

  351skip_line :-
  352    skip(10).
  353skip_line(Stream) :-
  354    skip(Stream, 10).
  355
  356
  357                 /*******************************
  358                 *         COMPILATION          *
  359                 *******************************/

 compile(+Files) is det

Compile files. SWI-Prolog doesn't distinguish between compilation and consult.

See also

- load_files/2.

  368:- meta_predicate
  369    compile(:).  370
  371compile(Files) :-
  372    consult(Files).
  373
  374                 /*******************************
  375                 *         ATOM-HANDLING        *
  376                 *******************************/

 atom_char(+Char, -Code) is det

atom_char(-Char, +Code) is det

Same as ISO char_code/2.

  383atom_char(Char, Code) :-
  384    char_code(Char, Code).

 midstring(?ABC, ?B, ?AC) is nondet

 midstring(?ABC, ?B, ?AC, LenA) is nondet

 midstring(?ABC, ?B, ?AC, LenA, LenB) is nondet

 midstring(?ABC, ?B, ?AC, LenA, LenB, LenC) is nondet

Too difficult to explain. See the Quintus docs. As far as I understand them the code below emulates this function just fine.

  394midstring(ABC, B, AC) :-
  395    midstring(ABC, B, AC, _, _, _).
  396midstring(ABC, B, AC, LenA) :-
  397    midstring(ABC, B, AC, LenA, _, _).
  398midstring(ABC, B, AC, LenA, LenB) :-
  399    midstring(ABC, B, AC, LenA, LenB, _).
  400midstring(ABC, B, AC, LenA, LenB, LenC) :-      % -ABC, +B, +AC
  401    var(ABC),
  402    !,
  403    atom_length(AC, LenAC),
  404    (   nonvar(LenA) ; nonvar(LenC)
  405    ->  plus(LenA, LenC, LenAC)
  406    ;   true
  407    ),
  408    sub_atom(AC, 0, LenA, _, A),
  409    LenC is LenAC - LenA,
  410    sub_atom(AC, _, LenC, 0, C),
  411    atom_length(B, LenB),
  412    atomic_list_concat([A,B,C], ABC).
  413midstring(ABC, B, AC, LenA, LenB, LenC) :-
  414    sub_atom(ABC, LenA, LenB, LenC, B),
  415    sub_atom(ABC, 0, LenA, _, A),
  416    sub_atom(ABC, _, LenC, 0, C),
  417    atom_concat(A, C, AC).
  418
  419
  420                 /*******************************
  421                 *           EXCEPTIONS         *
  422                 *******************************/

 raise_exception(+Term)

Quintus compatible exception handling

  428raise_exception(Term) :-
  429    throw(Term).

 on_exception(+Template, :Goal, :Recover)

  433:- meta_predicate
  434    on_exception(+, 0, 0).  435
  436on_exception(Except, Goal, Recover) :-
  437    catch(Goal, Except, Recover)