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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)  2010-2020, University of Amsterdam
    7                              CWI, Amsterdam
    8    All rights reserved.
    9
   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
   13
   14    1. Redistributions of source code must retain the above copyright
   15       notice, this list of conditions and the following disclaimer.
   16
   17    2. Redistributions in binary form must reproduce the above copyright
   18       notice, this list of conditions and the following disclaimer in
   19       the documentation and/or other materials provided with the
   20       distribution.
   21
   22    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   23    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   24    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   25    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   26    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   27    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   28    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   29    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   30    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   32    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   33    POSSIBILITY OF SUCH DAMAGE.
   34*/
   35
   36:- module(unicode,
   37          [ unicode_property/2,         % ?Code, ?Property
   38            unicode_map/3,              % +In, -Out, +Options
   39            unicode_nfd/2,              % +In, -Out
   40            unicode_nfc/2,              % +In, -Out
   41            unicode_nfkd/2,             % +In, -Out
   42            unicode_nfkc/2              % +In, -Out
   43          ]).   44:- use_foreign_library(foreign(unicode4pl)).   45
   46/** <module> Unicode string handling
   47
   48This       library       is       a       wrapper       around       the
   49[[utf8proc][http://www.public-software-group.org/utf8proc]]     library,
   50providing  information  about   Unicode    code-points   and  performing
   51operations  (mappings)  on  Unicode  atoms.  The  central  predicate  is
   52unicode_map/3, mapping a Unicode atom to   another  Unicode atom using a
   53sequence of operations.  The   predicates  unicode_nfd/2, unicode_nfc/2,
   54unicode_nfkd/2 and unicode_nfkc/2 implement the   four  standard Unicode
   55normalization forms.
   56
   57Lump handling:
   58
   59==
   60U+0020      <-- all space characters (general category Zs)
   61U+0027  '   <-- left/right single quotation mark U+2018..2019,
   62                modifier letter apostrophe U+02BC,
   63                modifier letter vertical line U+02C8
   64U+002D  -   <-- all dash characters (general category Pd),
   65                minus U+2212
   66U+002F  /   <-- fraction slash U+2044,
   67                division slash U+2215
   68U+003A  :   <-- ratio U+2236
   69U+003C  <   <-- single left-pointing angle quotation mark U+2039,
   70                left-pointing angle bracket U+2329,
   71                left angle bracket U+3008
   72U+003E  >   <-- single right-pointing angle quotation mark U+203A,
   73                right-pointing angle bracket U+232A,
   74                right angle bracket U+3009
   75U+005C  \   <-- set minus U+2216
   76U+005E  ^   <-- modifier letter up arrowhead U+02C4,
   77                modifier letter circumflex accent U+02C6,
   78                caret U+2038,
   79                up arrowhead U+2303
   80U+005F  _   <-- all connector characters (general category Pc),
   81                modifier letter low macron U+02CD
   82U+0060  `   <-- modifier letter grave accent U+02CB
   83U+007C  |   <-- divides U+2223
   84U+007E  ~   <-- tilde operator U+223C
   85==
   86
   87@see http://www.public-software-group.org/utf8proc
   88*/
   89
   90system:goal_expansion(unicode_map(In, Out, Options),
   91                      unicode_map(In, Out, Mask)) :-
   92    is_list(Options),
   93    unicode_option_mask(Options, Mask).
   94
   95%!  unicode_map(+In, -Out, +Options) is det.
   96%
   97%   Perform unicode normalization operations.  Options is a list
   98%   of operations.  Defined operations are:
   99%
  100%       * stable
  101%       Unicode Versioning Stability has to be respected.
  102%       * compat
  103%       Compatiblity decomposition (i.e. formatting information is lost)
  104%       * compose
  105%       Return a result with composed characters.
  106%       * decompose
  107%       Return a result with decomposed characters.
  108%       * ignore
  109%       Strip "default ignorable characters"
  110%       * rejectna
  111%       Return an error, if the input contains unassigned code
  112%       points.
  113%       * nlf2ls
  114%       Indicating that NLF-sequences (LF, CRLF, CR, NEL) are
  115%       representing a line break, and should be converted to the
  116%       unicode character for line separation (LS).
  117%       * nlf2ps
  118%       Indicating that NLF-sequences are representing a paragraph
  119%       break, and should be converted to the unicode character for
  120%       paragraph separation (PS).
  121%       * nlf2lf
  122%       Indicating that the meaning of NLF-sequences is unknown.
  123%       * stripcc
  124%       Strips and/or convers control characters.
  125%       NLF-sequences are transformed into space, except if one of
  126%       the NLF2LS/PS/LF options is given.
  127%       HorizontalTab (HT) and FormFeed (FF) are treated as a
  128%       NLF-sequence in this case.
  129%       All other control characters are simply removed.
  130%       * casefold
  131%       Performs unicode case folding, to be able to do a
  132%       case-insensitive string comparison.
  133%       * charbound
  134%       Inserts 0xFF bytes at the beginning of each sequence which
  135%       is representing a single grapheme cluster (see UAX#29).
  136%       * lump
  137%       (e.g. HYPHEN U+2010 and MINUS U+2212 to ASCII "-").
  138%       (See module header for details.)
  139%       If NLF2LF is set, this includes a transformation of
  140%       paragraph and line separators to ASCII line-feed (LF).
  141%       * stripmark
  142%       Strips all character markings
  143%       (non-spacing, spacing and enclosing) (i.e. accents)
  144%       NOTE: this option works only with =compose= or =decompose=.
  145
  146%!  unicode_nfd(+In, -Out) is det.
  147%
  148%   Characters are decomposed by canonical equivalence.
  149
  150unicode_nfd(In, Out) :-
  151    unicode_map(In, Out, [stable,decompose]).
  152
  153%!  unicode_nfc(+In, -Out) is det.
  154%
  155%   Characters are decomposed  and  then   recomposed  by  canonical
  156%   equivalence. It is possible for  the   result  to be a different
  157%   sequence of characters  than  the  original.
  158%
  159%   @see http://en.wikipedia.org/wiki/Unicode_equivalence#Normal_forms
  160
  161unicode_nfc(In, Out) :-
  162    unicode_map(In, Out, [stable,compose]).
  163
  164%!  unicode_nfkd(+In, -Out) is det.
  165%
  166%   Characters are decomposed by compatibility equivalence.
  167
  168unicode_nfkd(In, Out) :-
  169    unicode_map(In, Out, [stable,decompose,compat]).
  170
  171%!  unicode_nfkc(+In, -Out) is det.
  172%
  173%   Characters are decomposed  by   compatibility  equivalence, then
  174%   recomposed by canonical equivalence.
  175
  176unicode_nfkc(In, Out) :-
  177    unicode_map(In, Out, [stable,compose,compat]).
  178
  179
  180%!  unicode_property(?Char, ?Property) is nondet.
  181%
  182%   True if Property is defined for Char.  Property is a term
  183%   Name(Value).  Defined property-names are:
  184%
  185%       * category(atom)
  186%       Unicode code category of Char. This is   one  of Cc, Cf, Cn,
  187%       Co, Cs, Ll, Lm, Lo, Lt, Lu, Mc,  Me, Mn, Nd, Nl, No, Pc, Pd,
  188%       Pe, Pf, Pi, Po, Ps, Sc, Sk, Sm, So, Zl, Zp, Zs. When
  189%       testing, a single letter stands for all its subcategories.
  190%       E.g. to test form a letter, you can use
  191%
  192%           ==
  193%           unicode_property(C, category('L'))
  194%           ==
  195%
  196%       * combining_class(integer)
  197%       * bidi_class(atom)
  198%       * decomp_type(atom)
  199%       * decomp_mapping(list(code))
  200%       * bidi_mirrored(bool)
  201%       * uppercase_mapping(code)
  202%       * lowercase_mapping(code)
  203%       * titlecase_mapping(code)
  204%       * comb1st_index(code)
  205%       * comb2nd_index(code)
  206%       * comp_exclusion(bool)
  207%       * ignorable(bool)
  208%       * control_boundary(bool)
  209%       * extend(bool)
  210%       * casefold_mapping(list(code))
  211%
  212%   @tbd Complete documentation
  213
  214unicode_property(Code, Property) :-
  215    nonvar(Code), nonvar(Property),
  216    !,
  217    '$unicode_property'(Code, Property).
  218unicode_property(Code, Property) :-
  219    nonvar(Code),
  220    !,
  221    property(Property),
  222    '$unicode_property'(Code, Property).
  223unicode_property(Code, Property) :-
  224    var(Code),
  225    !,
  226    between(0, 0x10ffff, Code),
  227    property(Property),
  228    '$unicode_property'(Code, Property).
  229
  230property(category(_)).
  231property(combining_class(_)).
  232property(bidi_class(_)).
  233property(decomp_type(_)).
  234property(decomp_mapping(_)).
  235property(bidi_mirrored(_)).
  236property(uppercase_mapping(_)).
  237property(lowercase_mapping(_)).
  238property(titlecase_mapping(_)).
  239property(comb1st_index(_)).
  240property(comb2nd_index(_)).
  241property(comp_exclusion(_)).
  242property(ignorable(_)).
  243property(control_boundary(_)).
  244property(extend(_)).
  245property(casefold_mapping(_))