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



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().

       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
       SMILING 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
       naming conventions (:full)

       Anonymous hashes

           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");

       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

       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 charac-
       ter "\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 restriction should be lifted in a future
       version of Perl.



perl v5.8.8                       2001-09-21                      charnames(3)