/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (c) 1985-2025, University of Amsterdam
VU University Amsterdam
SWI-Prolog Solutions b.v.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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*/
:- module(quintus,
[ unix/1,
% file_exists/1,
abs/2,
sin/2,
cos/2,
tan/2,
log/2,
log10/2,
pow/3,
ceiling/2,
floor/2,
round/2,
acos/2,
asin/2,
atan/2,
atan2/3,
sign/2,
sqrt/2,
genarg/3,
no_style_check/1,
otherwise/0,
simple/1,
% statistics/2, % Please access as quintus:statistics/2
prolog_flag/2,
date/1, % -date(Year, Month, Day)
current_stream/3, % ?File, ?Mode, ?Stream
stream_position/3, % +Stream, -Old, +New
skip_line/0,
skip_line/1, % +Stream
compile/1, % +File(s)
atom_char/2,
midstring/3, % ABC, B, AC
midstring/4, % ABC, B, AC, LenA
midstring/5, % ABC, B, AC, LenA, LenB
midstring/6, % ABC, B, AC, LenA, LenB, LenC
raise_exception/1, % +Exception
on_exception/3 % +Ball, :Goal, :Recover
]).
:- autoload(library(apply),[maplist/3]).
:- autoload(library(date),[date_time_value/3]).
:- autoload(library(shell),[shell/0]).
/** <module> Quintus compatibility
This module defines several predicates from the Quintus Prolog
libraries. Note that our library structure is totally different. If this
library were complete, Prolog code could be ported by removing the
use_module/1 declarations, relying on the SWI-Prolog autoloader.
Bluffers guide to porting:
* Remove =|use_module(library(...))|=
* Run =|?- list_undefined.|=
* Fix problems
Of course, this library is incomplete ...
*/
/********************************
* SYSTEM INTERACTION *
*********************************/
%! 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.
unix(system(Command)) :-
shell(Command).
unix(shell(Command)) :-
shell(Command).
unix(shell) :-
shell.
unix(access(File, 0)) :-
access_file(File, read).
unix(cd) :-
expand_file_name(~, [Home]),
working_directory(_, Home).
unix(cd(Dir)) :-
working_directory(_, Dir).
unix(args(L)) :-
current_prolog_flag(os_argv, L).
unix(argv(L)) :-
current_prolog_flag(os_argv, S),
maplist(to_prolog, S, L).
to_prolog(S, A) :-
name(S, L),
name(A, L).
/********************************
* META PREDICATES *
*********************************/
%! otherwise
%
% For (A -> B ; otherwise -> C)
otherwise.
/********************************
* ARITHMETIC *
*********************************/
%! abs(+Number, -Absolute)
% Unify `Absolute' with the absolute value of `Number'.
abs(Number, Absolute) :-
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.
%
% @compat Quintus Prolog.
% @deprecated Do not use these predicates except for compatibility
% reasons.
sin(A, V) :- V is sin(A).
cos(A, V) :- V is cos(A).
tan(A, V) :- V is tan(A).
log(A, V) :- V is log(A).
log10(X, V) :- V is log10(X).
pow(X,Y,V) :- V is X**Y.
ceiling(X, V) :- V is ceil(X).
floor(X, V) :- V is floor(X).
round(X, V) :- V is round(X).
sqrt(X, V) :- V is sqrt(X).
acos(X, V) :- V is acos(X).
asin(X, V) :- V is asin(X).
atan(X, V) :- V is atan(X).
atan2(Y, X, V) :- V is atan(Y, X).
sign(X, V) :- V is sign(X).
/*******************************
* TERM MANIPULATION *
*******************************/
%! genarg(?Index, +Term, ?Arg) is nondet.
%
% Generalised version of ISO arg/3. SWI-Prolog's arg/3 is already
% genarg/3.
genarg(N, T, A) :-
arg(N, T, A).
/*******************************
* FLAGS *
*******************************/
%! prolog_flag(?Flag, ?Value) is nondet.
%
% Same as ISO current_prolog_flag/2. Maps =version=.
%
% @bug Should map relevant Quintus flag identifiers.
prolog_flag(version, Version) :-
!,
current_prolog_flag(version_data, swi(Major, Minor, Patch, _)),
current_prolog_flag(arch, Arch),
current_prolog_flag(compiled_at, Compiled),
atomic_list_concat(['SWI-Prolog ',
Major, '.', Minor, '.', Patch,
' (', Arch, '): ', Compiled], Version).
prolog_flag(Flag, Value) :-
current_prolog_flag(Flag, Value).
/*******************************
* STATISTICS *
*******************************/
% Here used to be a definition of Quintus statistics/2 in traditional
% SWI-Prolog statistics/2. The current built-in emulates Quintus
% almost completely.
/*******************************
* DATE/TIME *
*******************************/
%! date(-Date) is det.
%
% Get current date as date(Y,M,D)
date(Date) :-
get_time(T),
stamp_date_time(T, DaTime, local),
date_time_value(date, DaTime, Date).
/********************************
* STYLE CHECK *
*********************************/
%! no_style_check(Style) is det.
%
% Same as SWI-Prolog =|style_check(-Style)|=. The Quintus option
% =single_var= is mapped to =singleton=.
%
% @see style_check/1.
q_style_option(single_var, singleton) :- !.
q_style_option(Option, Option).
no_style_check(QOption) :-
q_style_option(QOption, SWIOption),
style_check(-SWIOption).
/*******************************
* TYPES *
*******************************/
%! simple(@Term) is semidet.
%
% Term is atomic or a variable.
simple(X) :-
( atomic(X)
-> true
; var(X)
).
/*******************************
* STREAMS *
*******************************/
%! current_stream(?Object, ?Mode, ?Stream)
%
% SICStus/Quintus and backward compatible predicate. New code should
% be using the ISO compatible stream_property/2.
current_stream(Object, Mode, Stream) :-
stream_property(Stream, mode(FullMode)),
stream_mode(FullMode, Mode),
( stream_property(Stream, file_name(Object0))
-> true
; stream_property(Stream, file_no(Object0))
-> true
; Object0 = []
),
Object = Object0.
stream_mode(read, read).
stream_mode(write, write).
stream_mode(append, write).
stream_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.
stream_position(Stream, Old, New) :-
stream_property(Stream, position(Old)),
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)|=.
skip_line :-
skip(10).
skip_line(Stream) :-
skip(Stream, 10).
/*******************************
* COMPILATION *
*******************************/
%! compile(+Files) is det.
%
% Compile files. SWI-Prolog doesn't distinguish between
% compilation and consult.
%
% @see load_files/2.
:- meta_predicate
compile(:).
compile(Files) :-
consult(Files).
/*******************************
* ATOM-HANDLING *
*******************************/
%! atom_char(+Char, -Code) is det.
%! atom_char(-Char, +Code) is det.
%
% Same as ISO char_code/2.
atom_char(Char, Code) :-
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.
midstring(ABC, B, AC) :-
midstring(ABC, B, AC, _, _, _).
midstring(ABC, B, AC, LenA) :-
midstring(ABC, B, AC, LenA, _, _).
midstring(ABC, B, AC, LenA, LenB) :-
midstring(ABC, B, AC, LenA, LenB, _).
midstring(ABC, B, AC, LenA, LenB, LenC) :- % -ABC, +B, +AC
var(ABC),
!,
atom_length(AC, LenAC),
( nonvar(LenA) ; nonvar(LenC)
-> plus(LenA, LenC, LenAC)
; true
),
sub_atom(AC, 0, LenA, _, A),
LenC is LenAC - LenA,
sub_atom(AC, _, LenC, 0, C),
atom_length(B, LenB),
atomic_list_concat([A,B,C], ABC).
midstring(ABC, B, AC, LenA, LenB, LenC) :-
sub_atom(ABC, LenA, LenB, LenC, B),
sub_atom(ABC, 0, LenA, _, A),
sub_atom(ABC, _, LenC, 0, C),
atom_concat(A, C, AC).
/*******************************
* EXCEPTIONS *
*******************************/
%! raise_exception(+Term)
%
% Quintus compatible exception handling
raise_exception(Term) :-
throw(Term).
%! on_exception(+Template, :Goal, :Recover)
:- meta_predicate
on_exception(+, 0, 0).
on_exception(Except, Goal, Recover) :-
catch(Goal, Except, Recover).