charnames(3) Perl Programmers Reference Guide charnames(3)NAMEcharnames - 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
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.
2001-02-22 perl v5.6.1 charnames(3)
