MirOS Manual: charnames(3p)


charnames(3p)   Perl Programmers Reference Guide    charnames(3p)

NAME

     charnames - define character names for "\N{named}" string
     literal escapes

SYNOPSIS

       use charnames ':full';
       print "\N{GREEK SMALL LETTER SIGMA} is called sigma.\n";

       use charnames ':short';
       print "\N{greek:Sigma} is an upper-case sigma.\n";

       use charnames qw(cyrillic greek);
       print "\N{sigma} is Greek sigma, and \N{be} is Cyrillic b.\n";

       use charnames ":full", ":alias" => {
         e_ACUTE => "LATIN SMALL LETTER E WITH ACUTE",
       };
       print "\N{e_ACUTE} is a small letter e with an acute.\n";

       use charnames ();
       print charnames::viacode(0x1234); # prints "ETHIOPIC SYLLABLE SEE"
       printf "%04X", charnames::vianame("GOTHIC LETTER AHSA"); # prints "10330"

DESCRIPTION

     Pragma "use charnames" supports arguments ":full", ":short",
     script names and customized aliases.  If ":full" is present,
     for expansion of "\N{CHARNAME}", the string "CHARNAME" is
     first looked up in the list of standard Unicode character
     names.  If ":short" is present, and "CHARNAME" has the form
     "SCRIPT:CNAME", then "CNAME" is looked up as a letter in
     script "SCRIPT".  If pragma "use charnames" is used with
     script name arguments, then for "\N{CHARNAME}" the name
     "CHARNAME" is looked up as a letter in the given scripts (in
     the specified order). Customized aliases are explained in
     "CUSTOM ALIASES".

     For lookup of "CHARNAME" inside a given script "SCRIPTNAME"
     this pragma looks for the names

       SCRIPTNAME CAPITAL LETTER CHARNAME
       SCRIPTNAME SMALL LETTER CHARNAME
       SCRIPTNAME LETTER CHARNAME

     in the table of standard Unicode names.  If "CHARNAME" is
     lowercase, then the "CAPITAL" variant is ignored, otherwise
     the "SMALL" variant is ignored.

     Note that "\N{...}" is compile-time, it's a special form of
     string constant used inside double-quoted strings: in other
     words, you cannot use variables inside the "\N{...}".  If
     you want similar run-time functionality, use
     charnames::vianame().

perl v5.8.8                2005-02-05                           1

charnames(3p)   Perl Programmers Reference Guide    charnames(3p)

     For the C0 and C1 control characters (U+0000..U+001F,
     U+0080..U+009F) as of Unicode 3.1, there are no official
     Unicode names but you can use instead the ISO 6429 names
     (LINE FEED, ESCAPE, and so forth).  In Unicode 3.2 (as of
     Perl 5.8) some naming changes take place ISO 6429 has been
     updated, see "ALIASES".  Also note that the U+UU80, U+0081,
     U+0084, and U+0099 do not have names even in ISO 6429.

     Since the Unicode standard uses "U+HHHH", so can you:
     "\N{U+263a}" is the Unicode smiley face, or "\N{WHITE SMIL-
     ING FACE}".

CUSTOM TRANSLATORS

     The mechanism of translation of "\N{...}" escapes is general
     and not hardwired into charnames.pm.  A module can install
     custom translations (inside the scope which "use"s the
     module) with the following magic incantation:

         use charnames ();           # for $charnames::hint_bits
         sub import {
             shift;
             $^H |= $charnames::hint_bits;
             $^H{charnames} = \&translator;
         }

     Here translator() is a subroutine which takes "CHARNAME" as
     an argument, and returns text to insert into the string
     instead of the "\N{CHARNAME}" escape.  Since the text to
     insert should be different in "bytes" mode and out of it,
     the function should check the current state of "bytes"-flag
     as in:

         use bytes ();                       # for $bytes::hint_bits
         sub translator {
             if ($^H & $bytes::hint_bits) {
                 return bytes_translator(@_);
             }
             else {
                 return utf8_translator(@_);
             }
         }

CUSTOM ALIASES

     This version of charnames supports three mechanisms of
     adding local or customized aliases to standard Unicode nam-
     ing conventions (:full)

     Anonymous hashes

perl v5.8.8                2005-02-05                           2

charnames(3p)   Perl Programmers Reference Guide    charnames(3p)

         use charnames ":full", ":alias" => {
             e_ACUTE => "LATIN SMALL LETTER E WITH ACUTE",
             };
         my $str = "\N{e_ACUTE}";

     Alias file

         use charnames ":full", ":alias" => "pro";

         will try to read "unicore/pro_alias.pl" from the @INC path. This
         file should return a list in plain perl:

         (
         A_GRAVE         => "LATIN CAPITAL LETTER A WITH GRAVE",
         A_CIRCUM        => "LATIN CAPITAL LETTER A WITH CIRCUMFLEX",
         A_DIAERES       => "LATIN CAPITAL LETTER A WITH DIAERESIS",
         A_TILDE         => "LATIN CAPITAL LETTER A WITH TILDE",
         A_BREVE         => "LATIN CAPITAL LETTER A WITH BREVE",
         A_RING          => "LATIN CAPITAL LETTER A WITH RING ABOVE",
         A_MACRON        => "LATIN CAPITAL LETTER A WITH MACRON",
         );

     Alias shortcut

         use charnames ":alias" => ":pro";

         works exactly the same as the alias pairs, only this time,
         ":full" is inserted automatically as first argument (if no
         other argument is given).

charnames::viacode(code)
     Returns the full name of the character indicated by the
     numeric code. The example

         print charnames::viacode(0x2722);

     prints "FOUR TEARDROP-SPOKED ASTERISK".

     Returns undef if no name is known for the code.

     This works only for the standard names, and does not yet
     apply to custom translators.

     Notice that the name returned for of U+FEFF is "ZERO WIDTH
     NO-BREAK SPACE", not "BYTE ORDER MARK".

charnames::vianame(name)
     Returns the code point indicated by the name. The example

         printf "%04X", charnames::vianame("FOUR TEARDROP-SPOKED ASTERISK");

perl v5.8.8                2005-02-05                           3

charnames(3p)   Perl Programmers Reference Guide    charnames(3p)

     prints "2722".

     Returns undef if the name is unknown.

     This works only for the standard names, and does not yet
     apply to custom translators.

ALIASES

     A few aliases have been defined for convenience: instead of
     having to use the official names

         LINE FEED (LF)
         FORM FEED (FF)
         CARRIAGE RETURN (CR)
         NEXT LINE (NEL)

     (yes, with parentheses) one can use

         LINE FEED
         FORM FEED
         CARRIAGE RETURN
         NEXT LINE
         LF
         FF
         CR
         NEL

     One can also use

         BYTE ORDER MARK
         BOM

     and

         ZWNJ
         ZWJ

     for ZERO WIDTH NON-JOINER and ZERO WIDTH JOINER.

     For backward compatibility one can use the old names for
     certain C0 and C1 controls

         old                         new

         HORIZONTAL TABULATION       CHARACTER TABULATION
         VERTICAL TABULATION         LINE TABULATION
         FILE SEPARATOR              INFORMATION SEPARATOR FOUR
         GROUP SEPARATOR             INFORMATION SEPARATOR THREE
         RECORD SEPARATOR            INFORMATION SEPARATOR TWO
         UNIT SEPARATOR              INFORMATION SEPARATOR ONE
         PARTIAL LINE DOWN           PARTIAL LINE FORWARD
         PARTIAL LINE UP             PARTIAL LINE BACKWARD

perl v5.8.8                2005-02-05                           4

charnames(3p)   Perl Programmers Reference Guide    charnames(3p)

     but the old names in addition to giving the character will
     also give a warning about being deprecated.

ILLEGAL CHARACTERS

     If you ask by name for a character that does not exist, a
     warning is given and the Unicode replacement character
     "\x{FFFD}" is returned.

     If you ask by code for a character that does not exist, no
     warning is given and "undef" is returned.  (Though if you
     ask for a code point past U+10FFFF you do get a warning.)

BUGS

     Since evaluation of the translation function happens in a
     middle of compilation (of a string literal), the translation
     function should not do any "eval"s or "require"s.  This res-
     triction should be lifted in a future version of Perl.

perl v5.8.8                2005-02-05                           5

Generated on 2014-07-04 21:17:45 by $MirOS: src/scripts/roff2htm,v 1.79 2014/02/10 00:36:11 tg Exp $

These manual pages and other documentation are copyrighted by their respective writers; their source is available at our CVSweb, AnonCVS, and other mirrors. The rest is Copyright © 2002‒2014 The MirOS Project, Germany.
This product includes material provided by Thorsten Glaser.

This manual page’s HTML representation is supposed to be valid XHTML/1.1; if not, please send a bug report – diffs preferred.