


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


NAME
       charnames - define character names for "\N{named}" string
       literal escape.

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";


DESCRIPTION
       Pragma "use charnames" supports arguments ":full",
       ":short" and script names.  If ":full" is present, for
       expansion of "\N{CHARNAME}}" string "CHARNAME" is first
       looked in the list of standard Unicode names of chars.  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).

       For lookup of "CHARNAME" inside a given script "SCRIPT-
       NAME" 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, other-
       wise the "SMALL" variant is ignored.

CUSTOM TRANSLATORS
       The mechanism of translation of "\N{...}" escapes is gen-
       eral 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



2001-05-24                 perl v5.6.1                          1





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


       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(@_);
               }
           }


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




































2001-05-24                 perl v5.6.1                          2


