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    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)  1985-2023, 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;
   30    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   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(backward_compatibility,
   38          [ '$arch'/2,
   39            '$version'/1,
   40            '$home'/1,
   41            '$argv'/1,
   42            '$set_prompt'/1,
   43            '$strip_module'/3,
   44            '$declare_module'/3,
   45            '$module'/2,
   46            at_initialization/1,        % :Goal
   47            displayq/1,
   48            displayq/2,
   49            sformat/2,                  % -String, +Fmt
   50            sformat/3,                  % -String, +Fmt, +Args
   51            concat/3,
   52            concat_atom/2,              % +List, -Atom
   53            concat_atom/3,              % +List, +Sep, -Atom
   54            '$apropos_match'/2,         % +Needle, +Hashstack
   55            read_clause/1,              % -Term
   56            read_clause/2,              % +Stream, -Term
   57            read_variables/2,           % -Term, -VariableNames
   58            read_variables/3,           % +Stream, -Term, -VariableNames
   59            read_pending_input/3,       % +Stream, -List, ?Tail
   60            feature/2,
   61            set_feature/2,
   62            substring/4,
   63            string_to_list/2,           % ?String, ?Codes
   64            string_to_atom/2,           % ?String, ?Atom
   65            flush/0,
   66            write_ln/1,                 % +Term
   67            proper_list/1,              % @Term
   68            free_variables/2,           % +Term, -Variables
   69            hash_term/2,                % +Term, -Hash
   70            checklist/2,                % :Goal, +List
   71            sublist/3,                  % :Goal, +List, -Sublist
   72            sumlist/2,                  % +List, -Sum
   73            convert_time/2,             % +Stamp, -String
   74            convert_time/8,             % +String, -YMDmhs.ms
   75            'C'/3,                      % +List, -Head, -Tail
   76            current_thread/2,           % ?Thread, ?Status
   77            current_mutex/3,            % ?Mutex, ?Owner, ?Count
   78            message_queue_size/2,       % +Queue, -TermsWaiting
   79            lock_predicate/2,           % +Name, +Arity
   80            unlock_predicate/2,         % +Name, +Arity
   81            current_module/2,           % ?Module, ?File
   82            export_list/2,              % +Module, -Exports
   83            call_cleanup/3,		% :Goal, ?Catcher, :Cleanup
   84            setup_and_call_cleanup/3,   % :Setup, :Goal, :Cleanup
   85            setup_and_call_cleanup/4,   % :Setup, :Goal, ?Catcher, :Cleanup
   86            merge/3,                    % +List1, +List2, -Union
   87            merge_set/3,                % +Set1, +Set2, -Union
   88            (index)/1,                  % :Head
   89            hash/1,                     % :PI
   90            set_base_module/1,          % :Base
   91            eval_license/0,
   92            trie_insert_new/3,		% +Trie, +Term, -Node
   93            thread_at_exit/1,           % :Goal
   94            read_history/6,             % +Show, +Help, +Special, +Prompt,
   95                                        % -Term, -Bindings
   96            '$sig_atomic'/1             % :Goal
   97          ]).   98:- autoload(library(apply),[maplist/3,maplist/2]).   99:- autoload(library(lists),[sum_list/2]).  100:- autoload(library(system),[lock_predicate/1,unlock_predicate/1]).  101
  102
  103:- meta_predicate
  104    at_initialization(0),
  105    call_cleanup(0,?,0),
  106    setup_and_call_cleanup(0,0,0),
  107    setup_and_call_cleanup(0,0,?,0),
  108    checklist(1, +),
  109    sublist(1, +, ?),
  110    index(:),
  111    hash(:),
  112    set_base_module(:),
  113    thread_at_exit(0),
  114    '$sig_atomic'(0).

Backward compatibility

This library defines predicates that used to exist in older version of SWI-Prolog, but are considered obsolete as there functionality is neatly covered by new features. Most often, these constructs are superseded by ISO-standard compliant predicates.

Please also note the existence of quintus.pl and edinburgh.pl for more compatibility predicates.

See also
- gxref/0 can be used to find files that import from library(backcomp) and thus reply on deprecated features. */
 $arch(-Architecture, -Version) is det
deprecated
- use current_prolog_flag(arch, Architecture)
  134'$arch'(Arch, unknown) :-
  135    current_prolog_flag(arch, Arch).
 $version(Version:integer) is det
deprecated
- use current_prolog_flag(version, Version)
  141'$version'(Version) :-
  142    current_prolog_flag(version, Version).
 $home(-SWIPrologDir) is det
See also
- file_search_path/2, absolute_file_name/3, The Prolog home directory is available through the alias swi.
deprecated
- use current_prolog_flag(home, SWIPrologDir)
  150'$home'(Home) :-
  151    current_prolog_flag(home, Home).
 $argv(-Argv:list) is det
deprecated
- use current_prolog_flag(os_argv, Argv) or current_prolog_flag(argv, Argv)
  158'$argv'(Argv) :-
  159    current_prolog_flag(os_argv, Argv).
 $set_prompt(+Prompt) is det
Set the prompt for the toplevel
deprecated
- use set_prolog_flag(toplevel_prompt, Prompt).
  167'$set_prompt'(Prompt) :-
  168    (   is_list(Prompt)
  169    ->  Prompt0 = Prompt
  170    ;   atom_codes(Prompt, Prompt0)
  171    ),
  172    maplist(percent_to_tilde, Prompt0, Prompt1),
  173    atom_codes(Atom, Prompt1),
  174    set_prolog_flag(toplevel_prompt, Atom).
  175
  176percent_to_tilde(0'%, 0'~) :- !.
  177percent_to_tilde(X, X).
 displayq(@Term) is det
 displayq(+Stream, @Term) is det
Write term ignoring operators and quote atoms.
deprecated
- Use write_term/3 or write_canonical/2.
  187displayq(Term) :-
  188    write_term(Term, [ignore_ops(true),quoted(true)]).
  189displayq(Stream, Term) :-
  190    write_term(Stream, Term, [ignore_ops(true),quoted(true)]).
 sformat(-String, +Format, +Args) is det
 sformat(-String, +Format) is det
deprecated
- Use format/3 as format(string(String), ...)
  198:- module_transparent sformat/2, sformat/3.  199
  200sformat(String, Format) :-
  201    format(string(String), Format, []).
  202sformat(String, Format, Arguments) :-
  203    format(string(String), Format, Arguments).
 concat(+Atom1, +Atom2, -Atom) is det
deprecated
- Use ISO atom_concat/3
  209concat(A, B, C) :-
  210    atom_concat(A, B, C).
 concat_atom(+List, -Atom) is det
Concatenate a list of atomic values to an atom.
deprecated
- Use atomic_list_concat/2 as proposed by the prolog commons initiative.
  219concat_atom([A, B], C) :-
  220    !,
  221    atom_concat(A, B, C).
  222concat_atom(L, Atom) :-
  223    atomic_list_concat(L, Atom).
 concat_atom(+List, +Separator, -Atom) is det
Concatenate a list of atomic values to an atom, inserting Separator between each consecutive elements.
deprecated
- Use atomic_list_concat/3 as proposed by the prolog commons initiative.
  234concat_atom(L, Sep, Atom) :-
  235    atomic_list_concat(L, Sep, Atom).
 $apropos_match(+Needle, +Haystack) is semidet
True if Needle is a sub atom of Haystack. Ignores the case of Haystack.
  242'$apropos_match'(Needle, Haystack) :-
  243    sub_atom_icasechk(Haystack, _, Needle).
 read_clause(-Term) is det
deprecated
- Use read_clause/3 or read_term/3.
  249read_clause(Term) :-
  250    read_clause(current_input, Term).
 read_clause(+Stream, -Term) is det
deprecated
- Use read_clause/3 or read_term/3.
  256read_clause(Stream, Term) :-
  257    read_clause(Stream, Term, [process_comment(false)]).
 read_variables(-Term, -Bindings) is det
 read_variables(+In:stream, -Term, -Bindings) is det
deprecated
- Use ISO read_term/2 or read_term/3.
  264read_variables(Term, Vars) :-
  265    read_term(Term, [variable_names(Vars)]).
  266
  267read_variables(Stream, Term, Vars) :-
  268    read_term(Stream, Term, [variable_names(Vars)]).
 read_pending_input(+Stream, -Codes, ?Tail) is det
deprecated
- Use read_pending_codes/3.
  274read_pending_input(Stream, Codes, Tail) :-
  275    read_pending_codes(Stream, Codes, Tail).
 feature(?Key, ?Value) is nondet
 set_feature(+Key, @Term) is det
Control Prolog flags.
deprecated
- Use ISO current_prolog_flag/2 and set_prolog_flag/2.
  284feature(Key, Value) :-
  285    current_prolog_flag(Key, Value).
  286
  287set_feature(Key, Value) :-
  288    set_prolog_flag(Key, Value).
 substring(+String, +Offset, +Length, -Sub)
Predecessor of sub_string using 1-based Offset.
deprecated
- Use sub_string/5.
  296substring(String, Offset, Length, Sub) :-
  297    Offset0 is Offset - 1,
  298    sub_string(String, Offset0, Length, _After, Sub).
 string_to_list(?String, ?Codes) is det
Bi-directional conversion between a string and a list of character codes.
deprecated
- Use string_codes/2.
  307string_to_list(String, Codes) :-
  308    string_codes(String, Codes).
 string_to_atom(?String, ?Atom) is det
Bi-directional conversion between string and atom.
deprecated
- Use atom_string/2. Note that the order of the arguments is reversed.
  317string_to_atom(Atom, String) :-
  318    atom_string(String, Atom).
 flush is det
deprecated
- use ISO flush_output/0.
  324flush :-
  325    flush_output.
 write_ln(X) is det
deprecated
- Use writeln(X).
  331write_ln(X) :-
  332    writeln(X).
 proper_list(+List)
Old SWI-Prolog predicate to check for a list that really ends in a []. There is not much use for the quick is_list, as in most cases you want to process the list element-by-element anyway.
deprecated
- Use ISO is_list/1.
  342proper_list(List) :-
  343    is_list(List).
 free_variables(+Term, -Variables)
Return a list of unbound variables in Term. The name term_variables/2 is more widely used.
deprecated
- Use term_variables/2.
  352free_variables(Term, Variables) :-
  353    term_variables(Term, Variables).
 hash_term(+Term, -Hash) is det
If Term is ground, Hash is unified to an integer representing a hash for Term. Otherwise Hash is left unbound.
deprecated
- Use term_hash/2.
  362hash_term(Term, Hash) :-
  363    term_hash(Term, Hash).
 checklist(:Goal, +List)
deprecated
- Use maplist/2
  370checklist(Goal, List) :-
  371    maplist(Goal, List).
 sublist(:Goal, +List1, ?List2)
Succeeds if List2 unifies with a list holding those terms for which call(Goal, Elem) succeeds.
deprecated
- Use include/3 from library(apply)
Compatibility
- DEC10 library
  381sublist(_, [], []) :- !.
  382sublist(Goal, [H|T], Sub) :-
  383    call(Goal, H),
  384    !,
  385    Sub = [H|R],
  386    sublist(Goal, T, R).
  387sublist(Goal, [_|T], R) :-
  388    sublist(Goal, T, R).
 sumlist(+List, -Sum) is det
True when Sum is the list of all numbers in List.
deprecated
- Use sum_list/2
  396sumlist(List, Sum) :-
  397    sum_list(List, Sum).
 $strip_module(+Term, -Module, -Plain)
This used to be an internal predicate. It was added to the XPCE compatibility library without $ and since then used at many places. From 5.4.1 onwards strip_module/3 is built-in and the $ variation is added here for compatibility.
deprecated
- Use strip_module/3.
  408:- module_transparent
  409    '$strip_module'/3.  410
  411'$strip_module'(Term, Module, Plain) :-
  412    strip_module(Term, Module, Plain).
 $module(-OldTypeIn, +NewTypeIn)
  416'$module'(OldTypeIn, NewTypeIn) :-
  417    '$current_typein_module'(OldTypeIn),
  418    '$set_typein_module'(NewTypeIn).
 $declare_module(Module, File, Line)
Used in triple20 particle library. Should use a public interface
  424'$declare_module'(Module, File, Line) :-
  425    '$declare_module'(Module, user, user, File, Line, false).
 at_initialization(:Goal) is det
Register goal only to be run if a saved state is restored.
deprecated
- Use initialization(Goal, restore)
  434at_initialization(Goal) :-
  435    initialization(Goal, restore).
 convert_time(+Stamp, -String)
Convert a time-stamp as obtained though get_time/1 into a textual representation using the C-library function ctime(). The value is returned as a SWI-Prolog string object (see section 4.23). See also convert_time/8.
deprecated
- Use format_time/3.
  447convert_time(Stamp, String) :-
  448    format_time(string(String), '%+', Stamp).
 convert_time(+Stamp, -Y, -Mon, -Day, -Hour, -Min, -Sec, -MilliSec)
Convert a time stamp, provided by get_time/1, time_file/2, etc. Year is unified with the year, Month with the month number (January is 1), Day with the day of the month (starting with 1), Hour with the hour of the day (0--23), Minute with the minute (0--59). Second with the second (0--59) and MilliSecond with the milliseconds (0--999). Note that the latter might not be accurate or might always be 0, depending on the timing capabilities of the system. See also convert_time/2.
deprecated
- Use stamp_date_time/3.
  463convert_time(Stamp, Y, Mon, Day, Hour, Min, Sec, MilliSec) :-
  464    stamp_date_time(Stamp,
  465                    date(Y, Mon, Day,
  466                         Hour, Min, FSec,
  467                         _, _, _),
  468                    local),
  469    Sec is integer(float_integer_part(FSec)),
  470    MilliSec is integer(float_fractional_part(FSec)*1000).
 C(?List, ?Head, ?Tail) is det
Used to be generated by DCG. Some people appear to be using in in normal code too.
deprecated
- Do not use in normal code; DCG no longer generates it.
  479'C'([H|T], H, T).
 current_thread(?Thread, ?Status) is nondet
deprecated
- Replaced by thread_property/2
  486current_thread(Thread, Status) :-
  487    nonvar(Thread),
  488    !,
  489    catch(thread_property(Thread, status(Status)),
  490          error(existence_error(thread, _), _),
  491          fail).
  492current_thread(Thread, Status) :-
  493    thread_property(Thread, status(Status)).
 current_mutex(?Mutex, ?Owner, ?Count) is nondet
deprecated
- Replaced by mutex_property/2
  499current_mutex(Mutex, Owner, Count) :-
  500    nonvar(Mutex),
  501    !,
  502    catch(mutex_property(Mutex, status(Status)),
  503          error(existence_error(mutex, _), _),
  504          fail),
  505    map_mutex_status(Status, Owner, Count).
  506current_mutex(Mutex, Owner, Count) :-
  507    mutex_property(Mutex, status(Status)),
  508    map_mutex_status(Status, Owner, Count).
  509
  510map_mutex_status(unlocked, [], 0).
  511map_mutex_status(locked(Owner, Count), Owner, Count).
 message_queue_size(+Queue, -Size) is det
True if Queue holds Size terms.
deprecated
- Please use message_queue_property(Queue, Size)
  520message_queue_size(Queue, Size) :-
  521    message_queue_property(Queue, size(Size)).
 lock_predicate(+Name, +Arity) is det
 unlock_predicate(+Name, +Arity) is det
deprecated
- see lock_predicate/1 and unlock_predicate/1.
  528:- module_transparent
  529    lock_predicate/2,
  530    unlock_predicate/2.  531
  532lock_predicate(Name, Arity) :-
  533    lock_predicate(Name/Arity).
  534
  535unlock_predicate(Name, Arity) :-
  536    unlock_predicate(Name/Arity).
 current_module(?Module, ?File) is nondet
True if Module is a module loaded from File.
deprecated
- Use module_property(Module, file(File))
  544current_module(Module, File) :-
  545    module_property(Module, file(File)).
 export_list(+Module, -List) is det
Module exports the predicates of List.
deprecated
- Use module_property(Module, exports(List))
  553export_list(Module, List) :-
  554    module_property(Module, exports(List)).
 call_cleanup(:Goal, +Catcher, :Cleanup)
Call Cleanup with an indication of the reason unified to Catcher.
deprecated
- Use setup_call_catcher_cleanup/4.
  562call_cleanup(Goal, Catcher, Cleanup) :-
  563    setup_call_catcher_cleanup(true, Goal, Catcher, Cleanup).
 setup_and_call_cleanup(:Setup, :Goal, :Cleanup)
Call Cleanup once after Goal is finished.
deprecated
- Use setup_call_cleanup/3.
  571setup_and_call_cleanup(Setup, Goal, Cleanup) :-
  572    setup_call_cleanup(Setup, Goal, Cleanup).
 setup_and_call_cleanup(:Setup, :Goal, Catcher, :Cleanup)
Call Cleanup once after Goal is finished, with Catcher unified to the reason
deprecated
- Use setup_call_cleanup/3.
  581setup_and_call_cleanup(Setup, Goal, Catcher, Cleanup) :-
  582    setup_call_catcher_cleanup(Setup, Goal, Catcher,Cleanup).
 merge_set(+Set1, +Set2, -Set3)
Merge the ordered sets Set1 and Set2 into a new ordered set without duplicates.
deprecated
- New code should use ord_union/3 from library(ordsets)
  592merge_set([], L, L) :- !.
  593merge_set(L, [], L) :- !.
  594merge_set([H1|T1], [H2|T2], [H1|R]) :- H1 @< H2, !, merge_set(T1, [H2|T2], R).
  595merge_set([H1|T1], [H2|T2], [H2|R]) :- H1 @> H2, !, merge_set([H1|T1], T2, R).
  596merge_set([H1|T1], [H2|T2], [H1|R]) :- H1 == H2,    merge_set(T1, T2, R).
 merge(+List1, +List2, -List3)
Merge the ordered sets List1 and List2 into a new ordered list. Duplicates are not removed and their order is maintained.
deprecated
- The name of this predicate is far too general for a rather specific function.
  607merge([], L, L) :- !.
  608merge(L, [], L) :- !.
  609merge([H1|T1], [H2|T2], [H|R]) :-
  610    (   H1 @=< H2
  611    ->  H = H1,
  612        merge(T1, [H2|T2], R)
  613    ;   H = H2,
  614        merge([H1|T1], T2, R)
  615    ).
 index(:Head) is det
Prepare the predicate indicated by Head for multi-argument indexing.
deprecated
- As of version 5.11.29, SWI-Prolog performs just-in-time indexing on all arguments.
  625index(Head) :-
  626    print_message(warning, decl_no_effect(index(Head))).
 hash(:PredInd) is det
Demands PredInd to be indexed using a hash-table. This is handled dynamically.
  633hash(PI) :-
  634    print_message(warning, decl_no_effect(hash(PI))).
 set_base_module(:Base) is det
Set the default module from which we inherit.
deprecated
- Equivalent to set_module(base(Base)).
  642set_base_module(M:Base) :-
  643    set_module(M:base(Base)).
 eval_license is det
deprecated
- Equivalent to license/0
  649eval_license :-
  650    license.
 trie_insert_new(+Trie, +Term, -Handle) is semidet
deprecated
- use trie_insert/4.
  656trie_insert_new(Trie, Term, Handle) :-
  657    trie_insert(Trie, Term, [], Handle).
 thread_at_exit(:Goal) is det
Register Goal to be called when the calling thread exits. @deprecated use prolog_listen(this_thread_exit, Goal)
  664thread_at_exit(Goal) :-
  665    prolog_listen(this_thread_exit, Goal).
 read_history(+Show, +Help, +Special, +Prompt, -Term, -Bindings)
deprecated
- use read_term_with_history/2.
  671read_history(Show, Help, Special, Prompt, Term, Bindings) :-
  672    read_term_with_history(
  673        Term,
  674        [ show(Show),
  675          help(Help),
  676          no_save(Special),
  677          prompt(Prompt),
  678          variable_names(Bindings)
  679        ]).
 $sig_atomic(:Goal)
Execute Goal without processing signals.
deprecated
- use sig_atomic/1.
  687'$sig_atomic'(Goal) :-
  688    sig_atomic(Goal)