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                              CWI, Amsterdam
    9                              SWI-Prolog Solutions b.v.
   10    All rights reserved.
   11
   12    Redistribution and use in source and binary forms, with or without
   13    modification, are permitted provided that the following conditions
   14    are met:
   15
   16    1. Redistributions of source code must retain the above copyright
   17       notice, this list of conditions and the following disclaimer.
   18
   19    2. Redistributions in binary form must reproduce the above copyright
   20       notice, this list of conditions and the following disclaimer in
   21       the documentation and/or other materials provided with the
   22       distribution.
   23
   24    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   25    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   26    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   27    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   28    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   29    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   30    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   31    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   32    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   33    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   34    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   35    POSSIBILITY OF SUCH DAMAGE.
   36*/
   37
   38:- module(shell,
   39          [ shell/0,
   40            ls/0,
   41            ls/1,                               % +Pattern
   42            cd/0,
   43            cd/1,                               % +Dir
   44            pushd/0,
   45            pushd/1,                            % +Dir
   46            dirs/0,
   47            pwd/0,
   48            popd/0,
   49            mv/2,                               % +File1, +File2
   50            rm/1                                % +File1
   51          ]).   52:- autoload(library(apply),[maplist/3,maplist/2]).   53:- autoload(library(error),
   54	    [existence_error/2,instantiation_error/1,must_be/2]).   55:- autoload(library(lists),[nth1/3]).   56
   57:- multifile
   58    file_style/2.                               % ++FileName, =Style
   59
   60
   61:- set_prolog_flag(generate_debug_info, false).

 shell

Execute an interactive shell. The following options are tried to find a suitable shell command:

1. The Prolog flag shell
2. The environment variable $SHELL
3. The Prolog flag posix_shell
4. The environment variable %comspec% (Windows only)

Errors

- existence_error(config, shell) if no suitable shell can be found.

   83shell :-
   84    interective_shell(Shell),
   85    access_file(Shell, execute),
   86    !,
   87    shell(Shell).
   88shell :-
   89    existence_error(config, shell).
   90
   91interective_shell(Shell) :-
   92    current_prolog_flag(shell, Shell).
   93interective_shell(Shell) :-
   94    getenv('SHELL', Shell).
   95interective_shell(Shell) :-
   96    current_prolog_flag(posix_shell, Shell).
   97interective_shell(Shell) :-
   98    current_prolog_flag(windows, true),
   99    getenv(comspec, Shell).             % Windows

 cd

 cd(Dir)

Change working directory

  107cd :-
  108    cd(~).
  109
  110cd(Dir) :-
  111    name_to_file(Dir, Name),
  112    working_directory(_, Name).

 pushd

 pushd(+Dir)

 popd

 dirs

Manage the directory stack:

• pushd/1 is as cd/1, pushing th old directory on a stack
• pushd/0 swaps the current directory with the top of the stack
• popd/0 pops to the top of the stack
• dirs/0 lists the current directory and the stack.

  127:- dynamic
  128    stack/1.  129
  130pushd :-
  131    pushd(+1).
  132
  133pushd(N) :-
  134    integer(N),
  135    !,
  136    findall(D, stack(D), Ds),
  137    (   nth1(N, Ds, Go),
  138        retract(stack(Go))
  139    ->  pushd(Go),
  140        print_message(information, shell(directory(Go)))
  141    ;   warning('Directory stack not that deep', []),
  142        fail
  143    ).
  144pushd(Dir) :-
  145    name_to_file(Dir, Name),
  146    working_directory(Old, Name),
  147    asserta(stack(Old)).
  148
  149popd :-
  150    retract(stack(Dir)),
  151    !,
  152    working_directory(_, Dir),
  153    print_message(information, shell(directory(Dir))).
  154popd :-
  155    warning('Directory stack empty', []),
  156    fail.
  157
  158dirs :-
  159    working_directory(WD, WD),
  160    findall(D, stack(D), Dirs),
  161    maplist(dir_name, [WD|Dirs], Results),
  162    print_message(information, shell(file_set(Results))).

 pwd

Print current working directory

  168pwd :-
  169    working_directory(WD, WD),
  170    print_message(information, format('~w', [WD])).
  171
  172dir_name('/', '/') :- !.
  173dir_name(Path, Name) :-
  174    atom_concat(P, /, Path),
  175    !,
  176    dir_name(P, Name).
  177dir_name(Path, Name) :-
  178    current_prolog_flag(unix, true),
  179    expand_file_name('~', [Home0]),
  180    (   atom_concat(Home, /, Home0)
  181    ->  true
  182    ;   Home = Home0
  183    ),
  184    atom_concat(Home, FromHome, Path),
  185    !,
  186    atom_concat('~', FromHome, Name).
  187dir_name(Path, Path).

 ls

 ls(+Pattern)

Listing similar to Unix =ls -F=, flagging directories with =/=.

  194ls :-
  195    ls('.').
  196
  197ls(Spec) :-
  198    name_to_files(Spec, Matches),
  199    ls_(Matches).
  200
  201ls_([]) :-
  202    !,
  203    warning('No Match', []).
  204ls_([Dir]) :-
  205    exists_directory(Dir),
  206    !,
  207    atom_concat(Dir, '/*', Pattern),
  208    expand_file_name(Pattern, Files),
  209    maplist(tagged_file_in_dir, Files, Results),
  210    print_message(information, shell(file_set(Results))).
  211ls_(Files) :-
  212    maplist(tag_file, Files, Results),
  213    print_message(information, shell(file_set(Results))).
  214
  215tagged_file_in_dir(File, Result) :-
  216    file_base_name(File, Base),
  217    (   exists_directory(File)
  218    ->  atom_concat(Base, /, Label),
  219        Result = dir(File, Label)
  220    ;   Result = file(File, Base)
  221    ).
  222
  223tag_file(File, dir(File, Label)) :-
  224    exists_directory(File),
  225    !,
  226    atom_concat(File, /, Label).
  227tag_file(File, file(File,File)).

 mv(+From, +To) is det

Move (Rename) a file. If To is a directory, From is moved into the directory. Uses expand_file_name/2 on the From argument.

  234mv(From, To) :-
  235    name_to_files(From, Src),
  236    name_to_new_file(To, Dest),
  237    mv_(Src, Dest).
  238
  239mv_([One], Dest) :-
  240    \+ exists_directory(Dest),
  241    !,
  242    rename_file(One, Dest).
  243mv_(Multi, Dest) :-
  244    (   exists_directory(Dest)
  245    ->  maplist(mv_to_dir(Dest), Multi)
  246    ;   print_message(warning, format('Not a directory: ~w', [Dest])),
  247        fail
  248    ).
  249
  250mv_to_dir(Dest, Src) :-
  251    file_base_name(Src, Name),
  252    atomic_list_concat([Dest, Name], /, Target),
  253    rename_file(Src, Target).

 rm(+File) is det

Remove (unlink) a file

  259rm(File) :-
  260    name_to_file(File, A),
  261    delete_file(A).

 name_to_file(+Name, -File)

Convert Name into a single file.

  268name_to_file(Spec, File) :-
  269    name_to_files(Spec, Files),
  270    (   Files = [File]
  271    ->  true
  272    ;   print_message(warning, format('Ambiguous: ~w', [Spec])),
  273        fail
  274    ).
  275
  276name_to_new_file(Spec, File) :-
  277    name_to_files(Spec, Files, false),
  278    (   Files = [File]
  279    ->  true
  280    ;   print_message(warning, format('Ambiguous: ~w', [Spec])),
  281        fail
  282    ).
  283
  284name_to_files(Spec, Files) :-
  285    name_to_files(Spec, Files, true).
  286name_to_files(Spec, Files, Exists) :-
  287    name_to_files_(Spec, Files, Exists),
  288    (   Files == []
  289    ->  print_message(warning, format('No match: ~w', [Spec])),
  290        fail
  291    ;   true
  292    ).
  293
  294name_to_files_(Spec, Files, _) :-
  295    compound(Spec),
  296    compound_name_arity(Spec, _Alias, 1),
  297    !,
  298    findall(File,
  299            (   absolute_file_name(Spec, File,
  300                                   [ access(exist),
  301                                     file_type(directory),
  302                                     file_errors(fail),
  303                                     solutions(all)
  304                                   ])
  305            ;   absolute_file_name(Spec, File,
  306                                   [ access(exist),
  307                                     file_errors(fail),
  308                                     solutions(all)
  309                                   ])
  310            ),
  311            Files).
  312name_to_files_(Spec, Files, Exists) :-
  313    file_name_to_atom(Spec, S1),
  314    expand_file_name(S1, Files0),
  315    (   Exists == true,
  316        Files0 == [S1],
  317        \+ access_file(S1, exist)
  318    ->  warning('"~w" does not exist', [S1]),
  319        fail
  320    ;   Files = Files0
  321    ).
  322
  323file_name_to_atom(Spec, File) :-
  324    atomic(Spec),
  325    !,
  326    atom_string(File, Spec).
  327file_name_to_atom(Spec, File) :-
  328    phrase(segments(Spec), L),
  329    atomic_list_concat(L, /, File).
  330
  331segments(Var) -->
  332    { var(Var),
  333      !,
  334      instantiation_error(Var)
  335    }.
  336segments(A/B) -->
  337    !,
  338    segments(A),
  339    segments(B).
  340segments(A) -->
  341    { must_be(atomic, A) },
  342    [ A ].

 warning(+Fmt, +Args:list) is det

  346warning(Fmt, Args) :-
  347    print_message(warning, format(Fmt, Args)).
  348
  349:- multifile prolog:message//1.  350
  351prolog:message(shell(file_set(Files))) -->
  352    { catch(tty_size(_, Width), _, Width = 80)
  353    },
  354    table(Files, Width).
  355prolog:message(shell(directory(Path))) -->
  356    { dir_name(Path, Name) },
  357    [ '~w'-[Name] ].

 table(+List, +Width)//

Produce a tabular layout to list all elements of List on lines with a maximum width of Width. Elements are placed as ls does:

1  4  7
2  5  8
3  6

  370table(List, Width) -->
  371    { table_layout(List, Width, Layout),
  372      compound_name_arguments(Array, a, List)
  373    },
  374    table(0, Array, Layout).
  375
  376table(I, Array, Layout) -->
  377    { Cols = Layout.cols,
  378      Index is I // Cols + (I mod Cols) * Layout.rows + 1,
  379      (   (I+1) mod Cols =:= 0
  380      ->  NL = true
  381      ;   NL = false
  382      )
  383    },
  384    (   { arg(Index, Array, Item) }
  385    ->  table_cell(Item, Layout.col_width, NL)
  386    ;   []
  387    ),
  388    (   { I2 is I+1,
  389          I2 < Cols*Layout.rows
  390        }
  391    ->  (   { NL == true }
  392        ->  [ nl ]
  393        ;   []
  394        ),
  395        table(I2, Array, Layout)
  396    ;   []
  397    ).
  398
  399table_cell(Item, ColWidth, false) -->
  400    { label_length(Item, Len),
  401      Spaces is ColWidth - Len
  402    },
  403    table_cell_value(Item),
  404    [ '~|~t~*+'-[Spaces] ].
  405table_cell(Item, _ColWidth, true) -->
  406    table_cell_value(Item).
  407
  408table_cell_value(dir(_, Label)) ==>
  409    [ '~w'-[Label] ].
  410table_cell_value(file(File, Label)) ==>
  411    (   { file_style(File, Style) }
  412    ->  (   { Style == url }
  413        ->  [ url(File,Label) ]
  414        ;   [ ansi(Style, '~w', [Label]) ]
  415        )
  416    ;   [ '~w'-[Label] ]
  417    ).

 file_style(++File, =Style) is det

True when File should be listed as a terminal hyperlink. The default only links Prolog source files.

Arguments:

Style

- is either url to make a hyperlink or a valid style argument for ansi_format/3.

  427file_style(File, url) :-
  428    file_name_extension(_, Ext, File),
  429    link_file_extension(Ext),
  430    !.
  431
  432link_file_extension(Ext) :-
  433    user:prolog_file_type(Ext,source).

 table_layout(+Items, +PageWidth, -Layout:dict) is det

Compute the number of columns, rows and the column width to create a tabular layout for Items.

  440table_layout(Atoms, Width, _{cols:Cols, rows:Rows, col_width:ColWidth}) :-
  441    length(Atoms, L),
  442    longest(Atoms, Longest),
  443    Cols is max(1, Width // (Longest + 3)),
  444    Rows is integer(L / Cols + 0.49999),    % should be ceil/1
  445    ColWidth is Width // Cols.
  446
  447longest(List, Longest) :-
  448    longest(List, 0, Longest).
  449
  450longest([], M, M) :- !.
  451longest([H|T], Sofar, M) :-
  452    label_length(H, L),
  453    L >= Sofar,
  454    !,
  455    longest(T, L, M).
  456longest([_|T], S, M) :-
  457    longest(T, S, M).
  458
  459label_length(dir(_, Label), Len) =>
  460    atom_length(Label, Len).
  461label_length(file(_, Label), Len) =>
  462    atom_length(Label, Len)