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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)  2010-2023, VU University Amsterdam
    7                              CWI, 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(ansi_term,
   38          [ ansi_format/3,              % +Attr, +Format, +Args
   39            ansi_get_color/2,           % +Which, -rgb(R,G,B)
   40            ansi_hyperlink/2,           % +Stream,+Location
   41            ansi_hyperlink/3            % +Stream,+URL,+Label
   42          ]).   43:- autoload(library(error), [domain_error/2, must_be/2, instantiation_error/1]).   44:- autoload(library(lists), [append/3]).   45:- autoload(library(uri), [uri_file_name/2]).   46:- if(exists_source(library(time))).   47:- autoload(library(time), [call_with_time_limit/2]).   48:- endif.

Print decorated text to ANSI consoles

This library allows for exploiting the color and attribute facilities of most modern terminals using ANSI escape sequences. This library provides the following:

The behavior of this library is controlled by two Prolog flags:

[99, 111, 108, 111, 114, 95, 116, 101, 114, 109]
When true, activate the color output for this library. Otherwise simply call format/3.
[104, 121, 112, 101, 114, 108, 105, 110, 107, 95, 116, 101, 114, 109]
Emit terminal hyperlinks for url(Location) and url(URL, Label) elements of Prolog messages.
See also
- http://en.wikipedia.org/wiki/ANSI_escape_code */
   74:- multifile
   75    prolog:console_color/2,                     % +Term, -AnsiAttrs
   76    supports_get_color/0,
   77    hyperlink/2.                                % +Stream, +Spec
   78
   79
   80color_term_flag_default(true) :-
   81    stream_property(user_input, tty(true)),
   82    stream_property(user_error, tty(true)),
   83    stream_property(user_output, tty(true)),
   84    \+ getenv('TERM', dumb),
   85    !.
   86color_term_flag_default(false).
   87
   88init_color_term_flag :-
   89    color_term_flag_default(Default),
   90    create_prolog_flag(color_term, Default,
   91                       [ type(boolean),
   92                         keep(true)
   93                       ]),
   94    create_prolog_flag(hyperlink_term, false,
   95                       [ type(boolean),
   96                         keep(true)
   97                       ]).
   98
   99:- init_color_term_flag.  100
  101
  102:- meta_predicate
  103    keep_line_pos(+, 0).  104
  105:- multifile
  106    user:message_property/2.
 ansi_format(+ClassOrAttributes, +Format, +Args) is det
Format text with ANSI attributes. This predicate behaves as format/2 using Format and Args, but if the current_output is a terminal, it adds ANSI escape sequences according to Attributes. For example, to print a text in bold cyan, do
?- ansi_format([bold,fg(cyan)], 'Hello ~w', [world]).

Attributes is either a single attribute, a list thereof or a term that is mapped to concrete attributes based on the current theme (see prolog:console_color/2). The attribute names are derived from the ANSI specification. See the source for sgr_code/2 for details. Some commonly used attributes are:

bold
underline
fg(Color),bg(Color),hfg(Color),hbg(Color)
For fg(Color) and bg(Color), the colour name can be '#RGB' or '#RRGGBB'
fg8(Spec),bg8(Spec)
8-bit color specification. Spec is a colour name, h(Color) or an integer 0..255.
fg(R,G,B),bg(R,G,B)
24-bit (direct color) specification. The components are integers in the range 0..255.

Defined color constants are below. default can be used to access the default color of the terminal.

ANSI sequences are sent if and only if

  148ansi_format(Attr, Format, Args) :-
  149    ansi_format(current_output, Attr, Format, Args).
  150
  151ansi_format(Stream, Class, Format, Args) :-
  152    stream_property(Stream, tty(true)),
  153    current_prolog_flag(color_term, true),
  154    !,
  155    class_attrs(Class, Attr),
  156    phrase(sgr_codes_ex(Attr), Codes),
  157    atomic_list_concat(Codes, ;, Code),
  158    with_output_to(
  159        Stream,
  160        (   keep_line_pos(current_output, format('\e[~wm', [Code])),
  161            format(Format, Args),
  162            keep_line_pos(current_output, format('\e[0m'))
  163        )
  164    ),
  165    flush_output.
  166ansi_format(Stream, _Attr, Format, Args) :-
  167    format(Stream, Format, Args).
  168
  169sgr_codes_ex(X) -->
  170    { var(X),
  171      !,
  172      instantiation_error(X)
  173    }.
  174sgr_codes_ex([]) -->
  175    !.
  176sgr_codes_ex([H|T]) -->
  177    !,
  178    sgr_codes_ex(H),
  179    sgr_codes_ex(T).
  180sgr_codes_ex(Attr) -->
  181    (   { sgr_code(Attr, Code) }
  182    ->  (   { is_list(Code) }
  183        ->  list(Code)
  184        ;   [Code]
  185        )
  186    ;   { domain_error(sgr_code, Attr) }
  187    ).
  188
  189list([]) --> [].
  190list([H|T]) --> [H], list(T).
 sgr_code(+Name, -Code)
True when code is the Select Graphic Rendition code for Name. The defined names are given below. Note that most terminals only implement this partially.
resetall attributes off
bold
faint
italic
underline
blink(slow)
blink(rapid)
negative
conceal
crossed_out
font(primary)
font(N)Alternate font (1..8)
fraktur
underline(double)
intensity(normal)
fg(Name)Color name
bg(Name)Color name
framed
encircled
overlined
ideogram(underline)
right_side_line
ideogram(underline(double))
right_side_line(double)
ideogram(overlined)
left_side_line
ideogram(stress_marking)
-OffSwitch attributes off
hfg(Name)Color name
hbg(Name)Color name
See also
- http://en.wikipedia.org/wiki/ANSI_escape_code
  232sgr_code(reset, 0).
  233sgr_code(bold,  1).
  234sgr_code(faint, 2).
  235sgr_code(italic, 3).
  236sgr_code(underline, 4).
  237sgr_code(blink(slow), 5).
  238sgr_code(blink(rapid), 6).
  239sgr_code(negative, 7).
  240sgr_code(conceal, 8).
  241sgr_code(crossed_out, 9).
  242sgr_code(font(primary), 10) :- !.
  243sgr_code(font(N), C) :-
  244    C is 10+N.
  245sgr_code(fraktur, 20).
  246sgr_code(underline(double), 21).
  247sgr_code(intensity(normal), 22).
  248sgr_code(fg(Name), C) :-
  249    (   ansi_color(Name, N)
  250    ->  C is N+30
  251    ;   rgb(Name, R, G, B)
  252    ->  sgr_code(fg(R,G,B), C)
  253    ).
  254sgr_code(bg(Name), C) :-
  255    !,
  256    (   ansi_color(Name, N)
  257    ->  C is N+40
  258    ;   rgb(Name, R, G, B)
  259    ->  sgr_code(bg(R,G,B), C)
  260    ).
  261sgr_code(framed, 51).
  262sgr_code(encircled, 52).
  263sgr_code(overlined, 53).
  264sgr_code(ideogram(underline), 60).
  265sgr_code(right_side_line, 60).
  266sgr_code(ideogram(underline(double)), 61).
  267sgr_code(right_side_line(double), 61).
  268sgr_code(ideogram(overlined), 62).
  269sgr_code(left_side_line, 62).
  270sgr_code(ideogram(stress_marking), 64).
  271sgr_code(-X, Code) :-
  272    off_code(X, Code).
  273sgr_code(hfg(Name), C) :-
  274    ansi_color(Name, N),
  275    C is N+90.
  276sgr_code(hbg(Name), C) :-
  277    !,
  278    ansi_color(Name, N),
  279    C is N+100.
  280sgr_code(fg8(Name), [38,5,N]) :-
  281    ansi_color8(Name, N).
  282sgr_code(bg8(Name), [48,5,N]) :-
  283    ansi_color8(Name, N).
  284sgr_code(fg(R,G,B), [38,2,R,G,B]) :-
  285    between(0, 255, R),
  286    between(0, 255, G),
  287    between(0, 255, B).
  288sgr_code(bg(R,G,B), [48,2,R,G,B]) :-
  289    between(0, 255, R),
  290    between(0, 255, G),
  291    between(0, 255, B).
  292
  293off_code(italic_and_franktur, 23).
  294off_code(underline, 24).
  295off_code(blink, 25).
  296off_code(negative, 27).
  297off_code(conceal, 28).
  298off_code(crossed_out, 29).
  299off_code(framed, 54).
  300off_code(overlined, 55).
  301
  302ansi_color8(h(Name), N) :-
  303    !,
  304    ansi_color(Name, N0),
  305    N is N0+8.
  306ansi_color8(Name, N) :-
  307    atom(Name),
  308    !,
  309    ansi_color(Name, N).
  310ansi_color8(N, N) :-
  311    between(0, 255, N).
  312
  313ansi_color(black,   0).
  314ansi_color(red,     1).
  315ansi_color(green,   2).
  316ansi_color(yellow,  3).
  317ansi_color(blue,    4).
  318ansi_color(magenta, 5).
  319ansi_color(cyan,    6).
  320ansi_color(white,   7).
  321ansi_color(default, 9).
  322
  323rgb(Name, R, G, B) :-
  324    atom_codes(Name, [0'#,R1,R2,G1,G2,B1,B2]),
  325    hex_color(R1,R2,R),
  326    hex_color(G1,G2,G),
  327    hex_color(B1,B2,B).
  328rgb(Name, R, G, B) :-
  329    atom_codes(Name, [0'#,R1,G1,B1]),
  330    hex_color(R1,R),
  331    hex_color(G1,G),
  332    hex_color(B1,B).
  333
  334hex_color(D1,D2,V) :-
  335    code_type(D1, xdigit(V1)),
  336    code_type(D2, xdigit(V2)),
  337    V is 16*V1+V2.
  338
  339hex_color(D1,V) :-
  340    code_type(D1, xdigit(V1)),
  341    V is 16*V1+V1.
 prolog:console_color(+Term, -AnsiAttributes) is semidet
Hook that allows for mapping abstract terms to concrete ANSI attributes. This hook is used by theme files to adjust the rendering based on user preferences and context. Defaults are defined in the file boot/messages.pl.
See also
- library(theme/dark) for an example implementation and the Term values used by the system messages.
  354                 /*******************************
  355                 *             HOOK             *
  356                 *******************************/
 prolog:message_line_element(+Stream, +Term) is semidet
Hook implementation that deals with ansi(+Attr, +Fmt, +Args) in message specifications.
  363prolog:message_line_element(S, ansi(Class, Fmt, Args)) :-
  364    class_attrs(Class, Attr),
  365    ansi_format(S, Attr, Fmt, Args).
  366prolog:message_line_element(S, ansi(Class, Fmt, Args, Ctx)) :-
  367    class_attrs(Class, Attr),
  368    ansi_format(S, Attr, Fmt, Args),
  369    (   nonvar(Ctx),
  370        Ctx = ansi(_, RI-RA)
  371    ->  keep_line_pos(S, format(S, RI, RA))
  372    ;   true
  373    ).
  374prolog:message_line_element(S, url(Location)) :-
  375    ansi_hyperlink(S, Location).
  376prolog:message_line_element(S, url(URL, Label)) :-
  377    ansi_hyperlink(S, URL, Label).
  378prolog:message_line_element(S, begin(Level, Ctx)) :-
  379    level_attrs(Level, Attr),
  380    stream_property(S, tty(true)),
  381    current_prolog_flag(color_term, true),
  382    !,
  383    (   is_list(Attr)
  384    ->  sgr_codes(Attr, Codes),
  385        atomic_list_concat(Codes, ;, Code)
  386    ;   sgr_code(Attr, Code)
  387    ),
  388    keep_line_pos(S, format(S, '\e[~wm', [Code])),
  389    Ctx = ansi('\e[0m', '\e[0m\e[~wm'-[Code]).
  390prolog:message_line_element(S, end(Ctx)) :-
  391    nonvar(Ctx),
  392    Ctx = ansi(Reset, _),
  393    keep_line_pos(S, write(S, Reset)).
  394
  395sgr_codes([], []).
  396sgr_codes([H0|T0], [H|T]) :-
  397    sgr_code(H0, H),
  398    sgr_codes(T0, T).
  399
  400level_attrs(Level,         Attrs) :-
  401    user:message_property(Level, color(Attrs)),
  402    !.
  403level_attrs(Level,         Attrs) :-
  404    class_attrs(message(Level), Attrs).
  405
  406class_attrs(Class, Attrs) :-
  407    user:message_property(Class, color(Attrs)),
  408    !.
  409class_attrs(Class, Attrs) :-
  410    prolog:console_color(Class, Attrs),
  411    !.
  412class_attrs(Class, Attrs) :-
  413    '$messages':default_theme(Class, Attrs),
  414    !.
  415class_attrs(Attrs, Attrs).
 ansi_hyperlink(+Stream, +Location) is det
 ansi_hyperlink(+Stream, +URL, +Label) is det
Create a hyperlink for a terminal emulator. The file is fairly easy, but getting the line and column across is not as there seems to be no established standard. The current implementation emits, i.e., inserting a capital L before the line.
``file://AbsFileName[#LLine[:Column]]``
See also
- https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda
  429ansi_hyperlink(Stream, Location) :-
  430    hyperlink(Stream, url(Location)),
  431    !.
  432ansi_hyperlink(Stream, Location) :-
  433    location_label(Location, Label),
  434    ansi_hyperlink(Stream, Location, Label).
  435
  436location_label(File:Line:Column, Label) =>
  437    format(string(Label), '~w:~w:~w', [File,Line,Column]).
  438location_label(File:Line, Label) =>
  439    format(string(Label), '~w:~w', [File,Line]).
  440location_label(File, Label) =>
  441    format(string(Label), '~w', [File]).
  442
  443ansi_hyperlink(Stream, Location, Label) :-
  444    hyperlink(Stream, url(Location, Label)),
  445    !.
  446ansi_hyperlink(Stream, File:Line:Column, Label) :-
  447    !,
  448    (   url_file_name(URI, File)
  449    ->  format(Stream, '\e]8;;~w#~d:~d\e\\~w\e]8;;\e\\',
  450               [ URI, Line, Column, Label ])
  451    ;   format(Stream, '~w', [Label])
  452    ).
  453ansi_hyperlink(Stream, File:Line, Label) :-
  454    !,
  455    (   url_file_name(URI, File)
  456    ->  format(Stream, '\e]8;;~w#~w\e\\~w\e]8;;\e\\',
  457               [ URI, Line, Label ])
  458    ;   format(Stream, '~w:~w', [File, Line])
  459    ).
  460ansi_hyperlink(Stream, File, Label) :-
  461    (   url_file_name(URI, File)
  462    ->  format(Stream, '\e]8;;~w\e\\~w\e]8;;\e\\',
  463               [ URI, Label ])
  464    ;   format(Stream, '~w', [File])
  465    ).
 hyperlink(+Stream, +Spec) is semidet
Multifile hook that may be used to redefine ansi_hyperlink/2,3. If this predicate succeeds the system assumes the link has been written to Stream.
Arguments:
Spec- is either url(Location) or url(URL, Label). See ansi_hyperlink/2,3 for details.
  478:- dynamic has_lib_uri/1 as volatile.  479
  480url_file_name(URL, File) :-
  481    current_prolog_flag(hyperlink_term, true),
  482    (   has_lib_uri(true)
  483    ->  uri_file_name(URL, File)
  484    ;   exists_source(library(uri))
  485    ->  use_module(library(uri), [uri_file_name/2]),
  486        uri_file_name(URL, File),
  487        asserta(has_lib_uri(true))
  488    ;   asserta(has_lib_uri(false)),
  489        fail
  490    ).
 keep_line_pos(+Stream, :Goal)
Run goal without changing the position information on Stream. This is used to avoid that the exchange of ANSI sequences modifies the notion of, notably, the line_pos notion.
  498keep_line_pos(S, G) :-
  499    stream_property(S, position(Pos)),
  500    !,
  501    setup_call_cleanup(
  502        stream_position_data(line_position, Pos, LPos),
  503        G,
  504        set_stream(S, line_position(LPos))).
  505keep_line_pos(_, G) :-
  506    call(G).
 ansi_get_color(+Which, -RGB) is semidet
Obtain the RGB color for an ANSI color parameter. Which is either a color alias or an integer ANSI color id. Defined aliases are foreground and background. This predicate sends a request to the console (user_output) and reads the reply. This assumes an xterm compatible terminal.
Arguments:
RGB- is a term rgb(Red,Green,Blue). The color components are integers in the range 0..65535.
  520:- if(current_predicate(call_with_time_limit/2)).  521ansi_get_color(Which0, RGB) :-
  522    stream_property(user_input, tty(true)),
  523    stream_property(user_output, tty(true)),
  524    stream_property(user_error, tty(true)),
  525    supports_get_color,
  526    (   color_alias(Which0, Which)
  527    ->  true
  528    ;   must_be(between(0,15),Which0)
  529    ->  Which = Which0
  530    ),
  531    catch(keep_line_pos(user_output,
  532                        ansi_get_color_(Which, RGB)),
  533          time_limit_exceeded,
  534          no_xterm).
  535
  536supports_get_color :-
  537    getenv('TERM', Term),
  538    sub_atom(Term, 0, _, _, xterm),
  539    \+ getenv('TERM_PROGRAM', 'Apple_Terminal').
  540
  541color_alias(foreground, 10).
  542color_alias(background, 11).
  543
  544ansi_get_color_(Which, rgb(R,G,B)) :-
  545    format(codes(Id), '~w', [Which]),
  546    hex4(RH),
  547    hex4(GH),
  548    hex4(BH),
  549    phrase(("\e]", Id, ";rgb:", RH, "/", GH, "/", BH, "\a"), Pattern),
  550    call_with_time_limit(0.05,
  551                         with_tty_raw(exchange_pattern(Which, Pattern))),
  552    !,
  553    hex_val(RH, R),
  554    hex_val(GH, G),
  555    hex_val(BH, B).
  556
  557no_xterm :-
  558    print_message(warning, ansi(no_xterm_get_colour)),
  559    fail.
  560
  561hex4([_,_,_,_]).
  562
  563hex_val([D1,D2,D3,D4], V) :-
  564    code_type(D1, xdigit(V1)),
  565    code_type(D2, xdigit(V2)),
  566    code_type(D3, xdigit(V3)),
  567    code_type(D4, xdigit(V4)),
  568    V is (V1<<12)+(V2<<8)+(V3<<4)+V4.
  569
  570exchange_pattern(Which, Pattern) :-
  571    format(user_output, '\e]~w;?\a', [Which]),
  572    flush_output(user_output),
  573    read_pattern(user_input, Pattern, []).
  574
  575read_pattern(From, Pattern, NotMatched0) :-
  576    copy_term(Pattern, TryPattern),
  577    append(Skip, Rest, NotMatched0),
  578    append(Rest, RestPattern, TryPattern),
  579    !,
  580    echo(Skip),
  581    try_read_pattern(From, RestPattern, NotMatched, Done),
  582    (   Done == true
  583    ->  Pattern = TryPattern
  584    ;   read_pattern(From, Pattern, NotMatched)
  585    ).
 try_read_pattern(+From, +Pattern, -NotMatched)
  589try_read_pattern(_, [], [], true) :-
  590    !.
  591try_read_pattern(From, [H|T], [C|RT], Done) :-
  592    get_code(C),
  593    (   C = H
  594    ->  try_read_pattern(From, T, RT, Done)
  595    ;   RT = [],
  596        Done = false
  597    ).
  598
  599echo([]).
  600echo([H|T]) :-
  601    put_code(user_output, H),
  602    echo(T).
  603
  604:- else.  605ansi_get_color(_Which0, _RGB) :-
  606    fail.
  607:- endif.  608
  609
  610
  611:- multifile prolog:message//1.  612
  613prolog:message(ansi(no_xterm_get_colour)) -->
  614    [ 'Terminal claims to be xterm compatible,'-[], nl,
  615      'but does not report colour info'-[]
  616    ]