charnames

       sequences; also define character names

SYNOPSIS
        use charnames ':full';
        print "\N{GREEK SMALL LETTER SIGMA} is called sigma.\n";
        print "\N{LATIN CAPITAL LETTER E WITH VERTICAL LINE BELOW}",
              " is an officially named sequence of two Unicode characters\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",
          mychar => 0xE8000,  # Private use area
        };
        print "\N{e_ACUTE} is a small letter e with an acute.\n";
        print "\\N{mychar} allows me to name private use characters.\n";

        use charnames ();
        print charnames::viacode(0x1234); # prints "ETHIOPIC SYLLABLE SEE"
        printf "%04X", charnames::vianame("GOTHIC LETTER AHSA"); # prints
                                                                 # "10330"
        print charnames::vianame("LATIN CAPITAL LETTER A"); # prints 65 on
                                                            # ASCII platforms;
                                                            # 193 on EBCDIC
        print charnames::string_vianame("LATIN CAPITAL LETTER A"); # prints "A"

DESCRIPTION
       Pragma "use charnames" is used to gain access to the names of the
       Unicode characters and named character sequences, and to allow you to
       define your own character and character sequence names.

       All forms of the pragma enable use of the following 3 functions:

       o   "charnames::string_vianame(name)" for run-time lookup of a either a
           character name or a named character sequence, returning its string
           representation

       o   "charnames::vianame(name)" for run-time lookup of a character name
           (but not a named character sequence) to get its ordinal value (code
           point)

       o   "charnames::viacode(code)" for run-time lookup of a code point to
           get its Unicode name.

       All forms other than "use charnames ();" also enable the use of
       "\N{CHARNAME}" sequences to compile a Unicode character into a string,
       based on its name.

       Note that "\N{U+...}", where the ... is a hexadecimal number, also
       inserts a character into a string, but doesn't require the use of this
       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 "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 can
       override these, and 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-quotish strings; this means that you cannot
       use variables inside the "\N{...}".  If you want similar run-time
       functionality, use charnames::string_vianame().

       For the C0 and C1 control characters (U+0000..U+001F, U+0080..U+009F)
       there are no official Unicode names but you can use instead the ISO
       6429 names (LINE FEED, ESCAPE, and so forth, and their abbreviations,
       LF, ESC, ...).  In Unicode 3.2 (as of Perl 5.8) some naming changes
       took place, and ISO 6429 was updated, see "ALIASES".

       If the input name is unknown, "\N{NAME}" raises a warning and
       substitutes the Unicode REPLACEMENT CHARACTER (U+FFFD).

       For "\N{NAME}", it is a fatal error if "use bytes" is in effect and the
       input name is that of a character that won't fit into a byte (i.e.,
       whose ordinal is above 255).

       Otherwise, any string that includes a "\N{charname}" or
       "\N{U+code point}" will automatically have Unicode semantics (see "Byte
       and Character Semantics" in perlunicode).

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
           BOM

       and these abbreviations

           Abbreviation        Full Name

           CGJ                 COMBINING GRAPHEME JOINER
           FVS1                MONGOLIAN FREE VARIATION SELECTOR ONE
           FVS2                MONGOLIAN FREE VARIATION SELECTOR TWO
           FVS3                MONGOLIAN FREE VARIATION SELECTOR THREE
           LRE                 LEFT-TO-RIGHT EMBEDDING
           LRM                 LEFT-TO-RIGHT MARK
           LRO                 LEFT-TO-RIGHT OVERRIDE
           MMSP                MEDIUM MATHEMATICAL SPACE
           MVS                 MONGOLIAN VOWEL SEPARATOR
           NBSP                NO-BREAK SPACE
           NNBSP               NARROW NO-BREAK SPACE
           PDF                 POP DIRECTIONAL FORMATTING
           RLE                 RIGHT-TO-LEFT EMBEDDING
           RLM                 RIGHT-TO-LEFT MARK
           RLO                 RIGHT-TO-LEFT OVERRIDE
           SHY                 SOFT HYPHEN
           VS1                 VARIATION SELECTOR-1
           .
           .
           .
           VS256               VARIATION SELECTOR-256
           WJ                  WORD JOINER
           ZWJ                 ZERO WIDTH JOINER
           ZWNJ                ZERO WIDTH NON-JOINER
           ZWSP                ZERO WIDTH SPACE

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

           old                         new

           FILE SEPARATOR              INFORMATION SEPARATOR FOUR
           GROUP SEPARATOR             INFORMATION SEPARATOR THREE
           HORIZONTAL TABULATION       CHARACTER TABULATION
           HORIZONTAL TABULATION SET   CHARACTER TABULATION SET
           HORIZONTAL TABULATION WITH JUSTIFICATION    CHARACTER TABULATION
                                                       WITH JUSTIFICATION
           PARTIAL LINE DOWN           PARTIAL LINE FORWARD
           PARTIAL LINE UP             PARTIAL LINE BACKWARD
           RECORD SEPARATOR            INFORMATION SEPARATOR TWO
           REVERSE INDEX               REVERSE LINE FEED
           UNIT SEPARATOR              INFORMATION SEPARATOR ONE
           VERTICAL TABULATION         LINE TABULATION
           VERTICAL TABULATION SET     LINE TABULATION SET

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

           PRIVATE USE 1                          PRIVATE USE ONE, U+0091
           PRIVATE USE 2                          PRIVATE USE TWO, U+0092
           SGC                                    U+0099
           SINGLE GRAPHIC CHARACTER INTRODUCER    U+0099
           SINGLE-SHIFT 2                         SINGLE SHIFT TWO, U+008E
           SINGLE-SHIFT 3                         SINGLE SHIFT THREE, U+008F
           START OF PROTECTED AREA                START OF GUARDED AREA, U+0096

CUSTOM ALIASES
       You can add customized aliases to standard (":full") Unicode naming
       conventions.  The aliases override any standard definitions, so, if
       you're twisted enough, you can change "\N{LATIN CAPITAL LETTER A}" to
       mean "B", etc.

       Note that an alias should not be something that is a legal curly brace-
       enclosed quantifier (see "QUANTIFIERS" in perlreref).  For example
       "\N{123}" means to match 123 non-newline characters, and is not treated
       as a charnames alias.  Aliases are discouraged from beginning with
       anything other than an alphabetic character and from containing
       anything other than alphanumerics, spaces, dashes, parentheses, and
       underscores.  Currently they must be ASCII.

       An alias can map to either an official Unicode character name or to a
       numeric code point (ordinal).  The latter is useful for assigning names
       to code points in Unicode private use areas such as U+E800 through
       U+F8FF.  A numeric code point must be a non-negative integer or a
       string beginning with "U+" or "0x" with the remainder considered to be
       a hexadecimal integer.  A literal numeric constant must be unsigned; it
       will be interpreted as hex if it has a leading zero or contains non-
       decimal hex digits; otherwise it will be interpreted as decimal.

       Aliases are added either by the use of anonymous hashes:

           use charnames ":alias" => {
               e_ACUTE => "LATIN SMALL LETTER E WITH ACUTE",
               mychar1 => 0xE8000,
               };
           my $str = "\N{e_ACUTE}";

       or by using a file containing aliases:

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

       This 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",

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

           print charnames::viacode(0x2722);

       prints "FOUR TEARDROP-SPOKED ASTERISK".

       The name returned is the official name for the code point, if
       available; otherwise your custom alias for it.  This means that your
       alias will only be returned for code points that don't have an official
       Unicode name (nor Unicode version 1 name), such as private use code
       points, and the 4 control characters U+0080, U+0081, U+0084, and
       U+0099.  If you define more than one name for the code point, it is
       indeterminate which one will be returned.

       The function returns "undef" if no name is known for the code point.
       In Unicode the proper name of these is the empty string, which "undef"
       stringifies to.  (If you ask for a code point past the legal Unicode
       maximum of U+10FFFF that you haven't assigned an alias to, you get
       "undef" plus a warning.)

       The input number must be a non-negative integer or a string beginning
       with "U+" or "0x" with the remainder considered to be a hexadecimal
       integer.  A literal numeric constant must be unsigned; it will be
       interpreted as hex if it has a leading zero or contains non-decimal hex
       digits; otherwise it will be interpreted as decimal.

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

charnames::string_vianame(name)
       This is a runtime equivalent to "\N{...}".  name can be any expression
       that evaluates to a name accepted by "\N{...}" under the ":full" option
       to "charnames".  In addition, any other options for the controlling
       "use charnames" in the same scope apply, like any script list, ":short"
       option, or custom aliases you may have defined.

       The only difference is that if the input name is unknown,
       "string_vianame" returns "undef" instead of the REPLACEMENT CHARACTER
       and does not raise a warning message.

charnames::vianame(name)
       This is similar to "string_vianame".  The main difference is that under
       most circumstances (see "BUGS" for the others), vianame returns an
       ordinal code point, whereas "string_vianame" returns a string.  For
       example,

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

       prints "U+2722".

       This leads to the other two differences.  Since a single code point is
               shift;
               $^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(@_);
               }
           }

       See "CUSTOM ALIASES" above for restrictions on CHARNAME.

       Of course, "vianame" and "viacode" would need to be overridden as well.

BUGS
       vianame normally returns an ordinal code point, but when the input name
       is of the form "U+...", it returns a chr instead.  In this case, if
       "use bytes" is in effect and the character won't fit into a byte, it
       returns "undef" and raises a warning.

       Names must be ASCII characters only, which means that you are out of
       luck if you want to create aliases in a language where some or all the
       characters of the desired aliases are non-ASCII.

       Since evaluation of the translation function (see "CUSTOM TRANSLATORS")
       happens in the middle of compilation (of a string literal), the
       translation function should not do any "eval"s or "require"s.  This
       restriction should be lifted (but is low priority) in a future version
       of Perl.



perl v5.14.2                      2011-09-26                  charnames(3perl)
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