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       perlunicook - cookbookish examples of handling Unicode in Perl


       This manpage contains short recipes demonstrating how to handle common Unicode operations
       in Perl, plus one complete program at the end. Any undeclared variables in individual
       recipes are assumed to have a previous appropriate value in them.


    0: Standard preamble
       Unless otherwise notes, all examples below require this standard preamble to work
       correctly, with the "#!" adjusted to work on your system:

        #!/usr/bin/env perl

        use utf8;      # so literals and identifiers can be in UTF-8
        use v5.12;     # or later to get "unicode_strings" feature
        use strict;    # quote strings, declare variables
        use warnings;  # on by default
        use warnings  qw(FATAL utf8);    # fatalize encoding glitches
        use open      qw(:std :encoding(UTF-8)); # undeclared streams in UTF-8
        use charnames qw(:full :short);  # unneeded in v5.16

       This does make even Unix programmers "binmode" your binary streams, or open them with
       ":raw", but that's the only way to get at them portably anyway.

       WARNING: "use autodie" (pre 2.26) and "use open" do not get along with each other.

    1: Generic Unicode-savvy filter
       Always decompose on the way in, then recompose on the way out.

        use Unicode::Normalize;

        while (<>) {
            $_ = NFD($_);   # decompose + reorder canonically
        } continue {
            print NFC($_);  # recompose (where possible) + reorder canonically

    2: Fine-tuning Unicode warnings
       As of v5.14, Perl distinguishes three subclasses of UTF‑8 warnings.

        use v5.14;                  # subwarnings unavailable any earlier
        no warnings "nonchar";      # the 66 forbidden non-characters
        no warnings "surrogate";    # UTF-16/CESU-8 nonsense
        no warnings "non_unicode";  # for codepoints over 0x10_FFFF

    3: Declare source in utf8 for identifiers and literals
       Without the all-critical "use utf8" declaration, putting UTF‑8 in your literals and
       identifiers won’t work right.  If you used the standard preamble just given above, this
       already happened.  If you did, you can do things like this:

        use utf8;

        my $measure   = "Ångström";
        my @μsoft     = qw( cp852 cp1251 cp1252 );
        my @ὑπέρμεγας = qw( ὑπέρ  μεγας );
        my @鯉        = qw( koi8-f koi8-u koi8-r );
        my $motto     = "👪 💗 🐪"; # FAMILY, GROWING HEART, DROMEDARY CAMEL

       If you forget "use utf8", high bytes will be misunderstood as separate characters, and
       nothing will work right.

    4: Characters and their numbers
       The "ord" and "chr" functions work transparently on all codepoints, not just on ASCII
       alone — nor in fact, not even just on Unicode alone.

        # ASCII characters

        # characters from the Basic Multilingual Plane

        # beyond the BMP
        ord("𝑛")               # MATHEMATICAL ITALIC SMALL N

        # beyond Unicode! (up to MAXINT)

    5: Unicode literals by character number
       In an interpolated literal, whether a double-quoted string or a regex, you may specify a
       character by its number using the "\x{HHHHHH}" escape.

        String: "\x{3a3}"
        Regex:  /\x{3a3}/

        String: "\x{1d45b}"
        Regex:  /\x{1d45b}/

        # even non-BMP ranges in regex work fine

    6: Get character name by number
        use charnames ();
        my $name = charnames::viacode(0x03A3);

    7: Get character number by name
        use charnames ();
        my $number = charnames::vianame("GREEK CAPITAL LETTER SIGMA");

    8: Unicode named characters
       Use the "\N{charname}" notation to get the character by that name for use in interpolated
       literals (double-quoted strings and regexes).  In v5.16, there is an implicit

        use charnames qw(:full :short);

       But prior to v5.16, you must be explicit about which set of charnames you want.  The
       ":full" names are the official Unicode character name, alias, or sequence, which all share
       a namespace.

        use charnames qw(:full :short latin greek);

        "\N{MATHEMATICAL ITALIC SMALL N}"      # :full
        "\N{GREEK CAPITAL LETTER SIGMA}"       # :full

       Anything else is a Perl-specific convenience abbreviation.  Specify one or more scripts by
       names if you want short names that are script-specific.

        "\N{Greek:Sigma}"                      # :short
        "\N{ae}"                               #  latin
        "\N{epsilon}"                          #  greek

       The v5.16 release also supports a ":loose" import for loose matching of character names,
       which works just like loose matching of property names: that is, it disregards case,
       whitespace, and underscores:

        "\N{euro sign}"                        # :loose (from v5.16)

    9: Unicode named sequences
       These look just like character names but return multiple codepoints.  Notice the %vx
       vector-print functionality in "printf".

        use charnames qw(:full);
        printf "U+%v04X\n", $seq;

    10: Custom named characters
       Use ":alias" to give your own lexically scoped nicknames to existing characters, or even
       to give unnamed private-use characters useful names.

        use charnames ":full", ":alias" => {
            ecute => "LATIN SMALL LETTER E WITH ACUTE",
            "APPLE LOGO" => 0xF8FF, # private use character

        "\N{APPLE LOGO}"

    11: Names of CJK codepoints
       Sinograms like “東京” come back with character names of "CJK UNIFIED IDEOGRAPH-6771" and
       "CJK UNIFIED IDEOGRAPH-4EAC", because their “names” vary.  The CPAN "Unicode::Unihan"
       module has a large database for decoding these (and a whole lot more), provided you know
       how to understand its output.

        # cpan -i Unicode::Unihan
        use Unicode::Unihan;
        my $str = "東京";
        my $unhan = Unicode::Unihan->new;
        for my $lang (qw(Mandarin Cantonese Korean JapaneseOn JapaneseKun)) {
            printf "CJK $str in %-12s is ", $lang;
            say $unhan->$lang($str);


        CJK 東京 in Mandarin     is DONG1JING1
        CJK 東京 in Cantonese    is dung1ging1
        CJK 東京 in Korean       is TONGKYENG
        CJK 東京 in JapaneseOn   is TOUKYOU KEI KIN
        CJK 東京 in JapaneseKun  is HIGASHI AZUMAMIYAKO

       If you have a specific romanization scheme in mind, use the specific module:

        # cpan -i Lingua::JA::Romanize::Japanese
        use Lingua::JA::Romanize::Japanese;
        my $k2r = Lingua::JA::Romanize::Japanese->new;
        my $str = "東京";
        say "Japanese for $str is ", $k2r->chars($str);


        Japanese for 東京 is toukyou

    12: Explicit encode/decode
       On rare occasion, such as a database read, you may be given encoded text you need to

         use Encode qw(encode decode);

         my $chars = decode("shiftjis", $bytes, 1);
        # OR
         my $bytes = encode("MIME-Header-ISO_2022_JP", $chars, 1);

       For streams all in the same encoding, don't use encode/decode; instead set the file
       encoding when you open the file or immediately after with "binmode" as described later

    13: Decode program arguments as utf8
            $ perl -CA ...
            $ export PERL_UNICODE=A
           use Encode qw(decode);
           @ARGV = map { decode('UTF-8', $_, 1) } @ARGV;

    14: Decode program arguments as locale encoding
           # cpan -i Encode::Locale
           use Encode qw(locale);
           use Encode::Locale;

           # use "locale" as an arg to encode/decode
           @ARGV = map { decode(locale => $_, 1) } @ARGV;

    15: Declare STD{IN,OUT,ERR} to be utf8
       Use a command-line option, an environment variable, or else call "binmode" explicitly:

            $ perl -CS ...
            $ export PERL_UNICODE=S
            use open qw(:std :encoding(UTF-8));
            binmode(STDIN,  ":encoding(UTF-8)");
            binmode(STDOUT, ":utf8");
            binmode(STDERR, ":utf8");

    16: Declare STD{IN,OUT,ERR} to be in locale encoding
           # cpan -i Encode::Locale
           use Encode;
           use Encode::Locale;

           # or as a stream for binmode or open
           binmode STDIN,  ":encoding(console_in)"  if -t STDIN;
           binmode STDOUT, ":encoding(console_out)" if -t STDOUT;
           binmode STDERR, ":encoding(console_out)" if -t STDERR;

    17: Make file I/O default to utf8
       Files opened without an encoding argument will be in UTF-8:

            $ perl -CD ...
            $ export PERL_UNICODE=D
            use open qw(:encoding(UTF-8));

    18: Make all I/O and args default to utf8
            $ perl -CSDA ...
            $ export PERL_UNICODE=SDA
            use open qw(:std :encoding(UTF-8));
            use Encode qw(decode);
            @ARGV = map { decode('UTF-8', $_, 1) } @ARGV;

    19: Open file with specific encoding
       Specify stream encoding.  This is the normal way to deal with encoded text, not by calling
       low-level functions.

        # input file
            open(my $in_file, "< :encoding(UTF-16)", "wintext");
            open(my $in_file, "<", "wintext");
            binmode($in_file, ":encoding(UTF-16)");
            my $line = <$in_file>;

        # output file
            open($out_file, "> :encoding(cp1252)", "wintext");
            open(my $out_file, ">", "wintext");
            binmode($out_file, ":encoding(cp1252)");
            print $out_file "some text\n";

       More layers than just the encoding can be specified here. For example, the incantation
       ":raw :encoding(UTF-16LE) :crlf" includes implicit CRLF handling.

    20: Unicode casing
       Unicode casing is very different from ASCII casing.

        uc("henry ⅷ")  # "HENRY Ⅷ"
        uc("tschüß")   # "TSCHÜSS"  notice ß => SS

        # both are true:
        "tschüß"  =~ /TSCHÜSS/i   # notice ß => SS
        "Σίσυφος" =~ /ΣΊΣΥΦΟΣ/i   # notice Σ,σ,ς sameness

    21: Unicode case-insensitive comparisons
       Also available in the CPAN Unicode::CaseFold module, the new "fc" “foldcase” function from
       v5.16 grants access to the same Unicode casefolding as the "/i" pattern modifier has
       always used:

        use feature "fc"; # fc() function is from v5.16

        # sort case-insensitively
        my @sorted = sort { fc($a) cmp fc($b) } @list;

        # both are true:
        fc("tschüß")  eq fc("TSCHÜSS")
        fc("Σίσυφος") eq fc("ΣΊΣΥΦΟΣ")

    22: Match Unicode linebreak sequence in regex
       A Unicode linebreak matches the two-character CRLF grapheme or any of seven vertical
       whitespace characters.  Good for dealing with textfiles coming from different operating


        s/\R/\n/g;  # normalize all linebreaks to \n

    23: Get character category
       Find the general category of a numeric codepoint.

        use Unicode::UCD qw(charinfo);
        my $cat = charinfo(0x3A3)->{category};  # "Lu"

    24: Disabling Unicode-awareness in builtin charclasses
       Disable "\w", "\b", "\s", "\d", and the POSIX classes from working correctly on Unicode
       either in this scope, or in just one regex.

        use v5.14;
        use re "/a";

        # OR

        my($num) = $str =~ /(\d+)/a;

       Or use specific un-Unicode properties, like "\p{ahex}" and "\p{POSIX_Digit"}.  Properties
       still work normally no matter what charset modifiers ("/d /u /l /a /aa") should be effect.

    25: Match Unicode properties in regex with \p, \P
       These all match a single codepoint with the given property.  Use "\P" in place of "\p" to
       match one codepoint lacking that property.

        \pL, \pN, \pS, \pP, \pM, \pZ, \pC
        \p{Sk}, \p{Ps}, \p{Lt}
        \p{alpha}, \p{upper}, \p{lower}
        \p{Latin}, \p{Greek}
        \p{script_extensions=Latin}, \p{scx=Greek}
        \p{East_Asian_Width=Wide}, \p{EA=W}
        \p{Line_Break=Hyphen}, \p{LB=HY}
        \p{Numeric_Value=4}, \p{NV=4}

    26: Custom character properties
       Define at compile-time your own custom character properties for use in regexes.

        # using private-use characters
        sub In_Tengwar { "E000\tE07F\n" }

        if (/\p{In_Tengwar}/) { ... }

        # blending existing properties
        sub Is_GraecoRoman_Title {<<'END_OF_SET'}

        if (/\p{Is_GraecoRoman_Title}/ { ... }

    27: Unicode normalization
       Typically render into NFD on input and NFC on output. Using NFKC or NFKD functions
       improves recall on searches, assuming you've already done to the same text to be searched.
       Note that this is about much more than just pre- combined compatibility glyphs; it also
       reorders marks according to their canonical combining classes and weeds out singletons.

        use Unicode::Normalize;
        my $nfd  = NFD($orig);
        my $nfc  = NFC($orig);
        my $nfkd = NFKD($orig);
        my $nfkc = NFKC($orig);

    28: Convert non-ASCII Unicode numerics
       Unless you’ve used "/a" or "/aa", "\d" matches more than ASCII digits only, but Perl’s
       implicit string-to-number conversion does not current recognize these.  Here’s how to
       convert such strings manually.

        use v5.14;  # needed for num() function
        use Unicode::UCD qw(num);
        my $str = "got Ⅻ and ४५६७ and ⅞ and here";
        my @nums = ();
        while ($str =~ /(\d+|\N)/g) {  # not just ASCII!
           push @nums, num($1);
        say "@nums";   #     12      4567      0.875

        use charnames qw(:full);
        my $nv = num("\N{RUMI DIGIT ONE}\N{RUMI DIGIT TWO}");

    29: Match Unicode grapheme cluster in regex
       Programmer-visible “characters” are codepoints matched by "/./s", but user-visible
       “characters” are graphemes matched by "/\X/".

        # Find vowel *plus* any combining diacritics,underlining,etc.
        my $nfd = NFD($orig);
        $nfd =~ / (?=[aeiou]) \X /xi

    30: Extract by grapheme instead of by codepoint (regex)
        # match and grab five first graphemes
        my($first_five) = $str =~ /^ ( \X{5} ) /x;

    31: Extract by grapheme instead of by codepoint (substr)
        # cpan -i Unicode::GCString
        use Unicode::GCString;
        my $gcs = Unicode::GCString->new($str);
        my $first_five = $gcs->substr(0, 5);

    32: Reverse string by grapheme
       Reversing by codepoint messes up diacritics, mistakenly converting "crème brûlée" into
       "éel̂urb em̀erc" instead of into "eélûrb emèrc"; so reverse by grapheme instead.  Both
       these approaches work right no matter what normalization the string is in:

        $str = join("", reverse $str =~ /\X/g);

        # OR: cpan -i Unicode::GCString
        use Unicode::GCString;
        $str = reverse Unicode::GCString->new($str);

    33: String length in graphemes
       The string "brûlée" has six graphemes but up to eight codepoints.  This counts by
       grapheme, not by codepoint:

        my $str = "brûlée";
        my $count = 0;
        while ($str =~ /\X/g) { $count++ }

         # OR: cpan -i Unicode::GCString
        use Unicode::GCString;
        my $gcs = Unicode::GCString->new($str);
        my $count = $gcs->length;

    34: Unicode column-width for printing
       Perl’s "printf", "sprintf", and "format" think all codepoints take up 1 print column, but
       many take 0 or 2.  Here to show that normalization makes no difference, we print out both

        use Unicode::GCString;
        use Unicode::Normalize;

        my @words = qw/crème brûlée/;
        @words = map { NFC($_), NFD($_) } @words;

        for my $str (@words) {
            my $gcs = Unicode::GCString->new($str);
            my $cols = $gcs->columns;
            my $pad = " " x (10 - $cols);
            say str, $pad, " |";

       generates this to show that it pads correctly no matter the normalization:

        crème      |
        crème      |
        brûlée     |
        brûlée     |

    35: Unicode collation
       Text sorted by numeric codepoint follows no reasonable alphabetic order; use the UCA for
       sorting text.

        use Unicode::Collate;
        my $col = Unicode::Collate->new();
        my @list = $col->sort(@old_list);

       See the ucsort program from the Unicode::Tussle CPAN module for a convenient command-line
       interface to this module.

    36: Case- and accent-insensitive Unicode sort
       Specify a collation strength of level 1 to ignore case and diacritics, only looking at the
       basic character.

        use Unicode::Collate;
        my $col = Unicode::Collate->new(level => 1);
        my @list = $col->sort(@old_list);

    37: Unicode locale collation
       Some locales have special sorting rules.

        # either use v5.12, OR: cpan -i Unicode::Collate::Locale
        use Unicode::Collate::Locale;
        my $col = Unicode::Collate::Locale->new(locale => "de__phonebook");
        my @list = $col->sort(@old_list);

       The ucsort program mentioned above accepts a "--locale" parameter.

    38: Making "cmp" work on text instead of codepoints
       Instead of this:

        @srecs = sort {
            $b->{AGE}   <=>  $a->{AGE}
            $a->{NAME}  cmp  $b->{NAME}
        } @recs;

       Use this:

        my $coll = Unicode::Collate->new();
        for my $rec (@recs) {
            $rec->{NAME_key} = $coll->getSortKey( $rec->{NAME} );
        @srecs = sort {
            $b->{AGE}       <=>  $a->{AGE}
            $a->{NAME_key}  cmp  $b->{NAME_key}
        } @recs;

    39: Case- and accent-insensitive comparisons
       Use a collator object to compare Unicode text by character instead of by codepoint.

        use Unicode::Collate;
        my $es = Unicode::Collate->new(
            level => 1,
            normalization => undef

         # now both are true:
        $es->eq("García",  "GARCIA" );
        $es->eq("Márquez", "MARQUEZ");

    40: Case- and accent-insensitive locale comparisons
       Same, but in a specific locale.

        my $de = Unicode::Collate::Locale->new(
                   locale => "de__phonebook",

        # now this is true:
        $de->eq("tschüß", "TSCHUESS");  # notice ü => UE, ß => SS

    41: Unicode linebreaking
       Break up text into lines according to Unicode rules.

        # cpan -i Unicode::LineBreak
        use Unicode::LineBreak;
        use charnames qw(:full);

        my $para = "This is a super\N{HYPHEN}long string. " x 20;
        my $fmt = Unicode::LineBreak->new;
        print $fmt->break($para), "\n";

    42: Unicode text in DBM hashes, the tedious way
       Using a regular Perl string as a key or value for a DBM hash will trigger a wide character
       exception if any codepoints won’t fit into a byte.  Here’s how to manually manage the

           use DB_File;
           use Encode qw(encode decode);
           tie %dbhash, "DB_File", "pathname";

        # STORE

           # assume $uni_key and $uni_value are abstract Unicode strings
           my $enc_key   = encode("UTF-8", $uni_key, 1);
           my $enc_value = encode("UTF-8", $uni_value, 1);
           $dbhash{$enc_key} = $enc_value;

        # FETCH

           # assume $uni_key holds a normal Perl string (abstract Unicode)
           my $enc_key   = encode("UTF-8", $uni_key, 1);
           my $enc_value = $dbhash{$enc_key};
           my $uni_value = decode("UTF-8", $enc_value, 1);

    43: Unicode text in DBM hashes, the easy way
       Here’s how to implicitly manage the translation; all encoding and decoding is done
       automatically, just as with streams that have a particular encoding attached to them:

           use DB_File;
           use DBM_Filter;

           my $dbobj = tie %dbhash, "DB_File", "pathname";
           $dbobj->Filter_Value("utf8");  # this is the magic bit

        # STORE

           # assume $uni_key and $uni_value are abstract Unicode strings
           $dbhash{$uni_key} = $uni_value;

         # FETCH

           # $uni_key holds a normal Perl string (abstract Unicode)
           my $uni_value = $dbhash{$uni_key};

    44: PROGRAM: Demo of Unicode collation and printing
       Here’s a full program showing how to make use of locale-sensitive sorting, Unicode casing,
       and managing print widths when some of the characters take up zero or two columns, not
       just one column each time.  When run, the following program produces this nicely aligned

           Crème Brûlée....... €2.00
           Éclair............. €1.60
           Fideuà............. €4.20
           Hamburger.......... €6.00
           Jamón Serrano...... €4.45
           Linguiça........... €7.00
           Pâté............... €4.15
           Pears.............. €2.00
           Pêches............. €2.25
           Smørbrød........... €5.75
           Spätzle............ €5.50
           Xoriço............. €3.00
           Γύρος.............. €6.50
           막걸리............. €4.00
           おもち............. €2.65
           お好み焼き......... €8.00
           シュークリーム..... €1.85
           寿司............... €9.99
           包子............... €7.50

       Here's that program; tested on v5.14.

        #!/usr/bin/env perl
        # umenu - demo sorting and printing of Unicode food
        # (obligatory and increasingly long preamble)
        use utf8;
        use v5.14;                       # for locale sorting
        use strict;
        use warnings;
        use warnings  qw(FATAL utf8);    # fatalize encoding faults
        use open      qw(:std :encoding(UTF-8)); # undeclared streams in UTF-8
        use charnames qw(:full :short);  # unneeded in v5.16

        # std modules
        use Unicode::Normalize;          # std perl distro as of v5.8
        use List::Util qw(max);          # std perl distro as of v5.10
        use Unicode::Collate::Locale;    # std perl distro as of v5.14

        # cpan modules
        use Unicode::GCString;           # from CPAN

        # forward defs
        sub pad($$$);
        sub colwidth(_);
        sub entitle(_);

        my %price = (
            "γύρος"             => 6.50, # gyros
            "pears"             => 2.00, # like um, pears
            "linguiça"          => 7.00, # spicy sausage, Portuguese
            "xoriço"            => 3.00, # chorizo sausage, Catalan
            "hamburger"         => 6.00, # burgermeister meisterburger
            "éclair"            => 1.60, # dessert, French
            "smørbrød"          => 5.75, # sandwiches, Norwegian
            "spätzle"           => 5.50, # Bayerisch noodles, little sparrows
            "包子"              => 7.50, # bao1 zi5, steamed pork buns, Mandarin
            "jamón serrano"     => 4.45, # country ham, Spanish
            "pêches"            => 2.25, # peaches, French
            "シュークリーム"    => 1.85, # cream-filled pastry like eclair
            "막걸리"            => 4.00, # makgeolli, Korean rice wine
            "寿司"              => 9.99, # sushi, Japanese
            "おもち"            => 2.65, # omochi, rice cakes, Japanese
            "crème brûlée"      => 2.00, # crema catalana
            "fideuà"            => 4.20, # more noodles, Valencian
                                         # (Catalan=fideuada)
            "pâté"              => 4.15, # gooseliver paste, French
            "お好み焼き"        => 8.00, # okonomiyaki, Japanese

        my $width = 5 + max map { colwidth } keys %price;

        # So the Asian stuff comes out in an order that someone
        # who reads those scripts won't freak out over; the
        # CJK stuff will be in JIS X 0208 order that way.
        my $coll  = Unicode::Collate::Locale->new(locale => "ja");

        for my $item ($coll->sort(keys %price)) {
            print pad(entitle($item), $width, ".");
            printf " €%.2f\n", $price{$item};

        sub pad($$$) {
            my($str, $width, $padchar) = @_;
            return $str . ($padchar x ($width - colwidth($str)));

        sub colwidth(_) {
            my($str) = @_;
            return Unicode::GCString->new($str)->columns;

        sub entitle(_) {
            my($str) = @_;
            $str =~ s{ (?=\pL)(\S)     (\S*) }
                     { ucfirst($1) . lc($2)  }xge;
            return $str;


       See these manpages, some of which are CPAN modules: perlunicode, perluniprops, perlre,
       perlrecharclass, perluniintro, perlunitut, perlunifaq, PerlIO, DB_File, DBM_Filter,
       DBM_Filter::utf8, Encode, Encode::Locale, Unicode::UCD, Unicode::Normalize,
       Unicode::GCString, Unicode::LineBreak, Unicode::Collate, Unicode::Collate::Locale,
       Unicode::Unihan, Unicode::CaseFold, Unicode::Tussle, Lingua::JA::Romanize::Japanese,
       Lingua::ZH::Romanize::Pinyin, Lingua::KO::Romanize::Hangul.

       The Unicode::Tussle CPAN module includes many programs to help with working with Unicode,
       including these programs to fully or partly replace standard utilities: tcgrep instead of
       egrep, uniquote instead of cat -v or hexdump, uniwc instead of wc, unilook instead of
       look, unifmt instead of fmt, and ucsort instead of sort.  For exploring Unicode character
       names and character properties, see its uniprops, unichars, and uninames programs.  It
       also supplies these programs, all of which are general filters that do Unicode-y things:
       unititle and unicaps; uniwide and uninarrow; unisupers and unisubs; nfd, nfc, nfkd, and
       nfkc; and uc, lc, and tc.

       Finally, see the published Unicode Standard (page numbers are from version 6.0.0),
       including these specific annexes and technical reports:

       §3.13 Default Case Algorithms, page 113; §4.2  Case, pages 120–122; Case Mappings, page
       166–172, especially Caseless Matching starting on page 170.
       UAX #44: Unicode Character Database
       UTS #18: Unicode Regular Expressions
       UAX #15: Unicode Normalization Forms
       UTS #10: Unicode Collation Algorithm
       UAX #29: Unicode Text Segmentation
       UAX #14: Unicode Line Breaking Algorithm
       UAX #11: East Asian Width


       Tom Christiansen <> wrote this, with occasional kibbitzing from Larry Wall
       and Jeffrey Friedl in the background.


       Copyright © 2012 Tom Christiansen.

       This program is free software; you may redistribute it and/or modify it under the same
       terms as Perl itself.

       Most of these examples taken from the current edition of the “Camel Book”; that is, from
       the 4ᵗʰ Edition of Programming Perl, Copyright © 2012 Tom Christiansen <et al.>,
       2012-02-13 by O’Reilly Media.  The code itself is freely redistributable, and you are
       encouraged to transplant, fold, spindle, and mutilate any of the examples in this manpage
       however you please for inclusion into your own programs without any encumbrance
       whatsoever.  Acknowledgement via code comment is polite but not required.


       v1.0.0 – first public release, 2012-02-27