NAME

UTF2 - Source code filter to escape UTF-2

SYNOPSIS

use UTF2;
use UTF2 version;         --- require version
use UTF2 qw(ord reverse); --- demand enhanced feature of ord and reverse
use UTF2 version qw(ord reverse);

# "no UTF2;" not supported

or

C:\>perl UTF2.pm UTF-2_script.pl > Escaped_script.pl.e

UTF-2_script.pl  --- script written in UTF-2
Escaped_script.pl.e --- escaped script

functions:
  UTF2::ord(...);
  UTF2::reverse(...);
  UTF2::length(...);
  UTF2::substr(...);
  UTF2::index(...);
  UTF2::rindex(...);

emulate Perl5.6 on perl5.005
  binmode(...);
  open(...);

dummy functions:
  utf8::upgrade(...);
  utf8::downgrade(...);
  utf8::encode(...);
  utf8::decode(...);
  utf8::is_utf8(...);
  utf8::valid(...);
  bytes::chr(...);
  bytes::index(...);
  bytes::length(...);
  bytes::ord(...);
  bytes::rindex(...);
  bytes::substr(...);

ABSTRACT

Let's start with a bit of history: jperl 4.019+1.3 introduced UTF-2 support. You could apply chop() and regexps even to complex CJK characters.

JPerl in CPAN Perl Ports (Binary Distributions)

http://www.cpan.org/ports/index.html#jperl

said,

As of Perl 5.8.0 it is suggested that instead of JPerl (which is
based on a quite old release of Perl) you should just use Perl 5.8.0,
since it can do all that JPerl did, and more.

But is it really so?

In this country, UTF-2 is widely used on mainframe I/O, the personal computer, and the cellular phone. This software treats UTF-2 directly. Therefor there is not UTF8 flag.

A difficult solution makes the problem more difficult. Shall we escape from the encode problem?

Yet Another Future Of

JPerl is very useful software. -- Oops, note, this "JPerl" means Japanized or Japanese Perl, so is unrelated to Java and JVM. Therefore, I named this software better, fitter UTF2.

Now, the last version of JPerl is 5.005_04 and is not maintained now.

Japanization modifier WATANABE Hirofumi said,

"Because WATANABE am tired I give over maintaing JPerl."

at Slide #15: "The future of JPerl" of

ftp://ftp.oreilly.co.jp/pcjp98/watanabe/jperlconf.ppt

in The Perl Confernce Japan 1998.

When I heard it, I thought that someone excluding me would maintain JPerl. And I slept every night hanging a sock. Night and day, I kept having hope. After 10 years, I noticed that white beard exists in the sock :-)

This software is a source code filter to escape Perl script encoded by UTF-2 given from STDIN or command line parameter. The character code is never converted by escaping the script. Neither the value of the character nor the length of the character string change even if it escapes.

What's this software good for ...

Possible to handle raw UTF-2 values
Backward compatibility of data, script and how to
Only UTF2.pm and Eutf2.pm, other modules are unnecessary
No UTF8 flag, perlunitut and perluniadvice
No C programming (for maintain JPerl)
Independent from binary file (CPU, OS, perl version, 32bit/64bit)

Let's make yet another future by JPerl's future.

BASIC IDEA

I discovered this mail again recently.

[Tokyo.pm] jus Benkyoukai

http://mail.pm.org/pipermail/tokyo-pm/1999-September/001854.html

save as: SJIS.pm

package SJIS;
use Filter::Util::Call;
sub multibyte_filter {
    my $status;
    if (($status = filter_read()) > 0 ) {
        s/([\x81-\x9f\xe0-\xef])([\x40-\x7e\x80-\xfc])/
            sprintf("\\x%02x\\x%02x",ord($1),ord($2))
        /eg;
    }
    $status;
}
sub import {
    filter_add(\&multibyte_filter);
}
1;

I am glad that I could confirm my idea is not so wrong.

SOFTWARE COMPOSITION

UTF2.pm               --- source code filter to escape UTF-2
Eutf2.pm              --- run-time routines for UTF2.pm
perl55.bat            --- find and run perl5.5  without %PATH% settings
perl56.bat            --- find and run perl5.6  without %PATH% settings
perl58.bat            --- find and run perl5.8  without %PATH% settings
perl510.bat           --- find and run perl5.10 without %PATH% settings
perl512.bat           --- find and run perl5.12 without %PATH% settings
perl64.bat            --- find and run perl64   without %PATH% settings
strict.pm_            --- dummy strict.pm
warnings.pm_          --- poor warnings.pm
warnings/register.pm_ --- poor warnings/register.pm

Rename and install strict.pm_ of this distribution to strict.pm if your system
doesn't have strict.pm.

Upper Compatibility By Escaping

This software adds the function by 'Escaping' it always, and nothing of the past is broken. Therefore, 'Possible job' never becomes 'Impossible job'. This approach is effective in the field where the retreat is never permitted. Modern Perl/perl can not always solve the problem.

Escaping Your Script (You do)

You need write 'use UTF2;' in your script.

---------------------------------
Before      After
---------------------------------
(nothing)   use UTF2;
---------------------------------

Escaping Multiple Octet Code (UTF2.pm provides)

Insert chr(0x5c) before @ [ \ ] ^ ` { | and } in multiple octet of

string in single quote ('', q{}, <<'END' and qw{})
string in double quote ("", qq{}, <<END, <<"END", ``, qx{} and <<`END`)
regexp in single quote (m'', s''', split(''), split(m'') and qr'')
regexp in double quote (//, m//, ??, s///, split(//), split(m//) and qr//)
character in tr/// (tr/// and y///)

 ex. Japanese Katakana "SO" like [ `/ ] code is "\x83\x5C" in SJIS

                 see     hex dump
 -----------------------------------------
 source script   "`/"    [83 5c]
 -----------------------------------------

 Here, use SJIS;
                         hex dump
 -----------------------------------------
 escaped script  "`\/"   [83 [5c] 5c]
 -----------------------------------------
                   ^--- escape by SJIS software

 by the by       see     hex dump
 -----------------------------------------
 your eye's      "`/\"   [83 5c] [5c]
 -----------------------------------------
 perl eye's      "`\/"   [83] \[5c]
 -----------------------------------------

                         hex dump
 -----------------------------------------
 in the perl     "`/"    [83] [5c]
 -----------------------------------------

Escaping Character Classes (Eutf2.pm provides)

The character classes are redefined as follows to backward compatibility.

---------------------------------------------------------------------------
Before      After
---------------------------------------------------------------------------
 .          (?:(?:[\xC2-\xDF]|[\xE0-\xE0][\xA0-\xBF]|[\xE1-\xEC][\x80-\xBF]|[\xED-\xED][\x80-\x9F]|[\xEE-\xEF][\x80-\xBF]|[\xF0-\xF0][\x90-\xBF][\x80-\xBF]|[\xF1-\xF3][\x80-\xBF][\x80-\xBF]|[\xF4-\xF4][\x80-\x8F][\x80-\xBF])[\x00-\xFF]|[^\x0A])
            (?:(?:[\xC2-\xDF]|[\xE0-\xE0][\xA0-\xBF]|[\xE1-\xEC][\x80-\xBF]|[\xED-\xED][\x80-\x9F]|[\xEE-\xEF][\x80-\xBF]|[\xF0-\xF0][\x90-\xBF][\x80-\xBF]|[\xF1-\xF3][\x80-\xBF][\x80-\xBF]|[\xF4-\xF4][\x80-\x8F][\x80-\xBF])[\x00-\xFF]|[\x00-\xFF]) (/s modifier)
\d          [0-9]
\s          [\x09\x0A\x0C\x0D\x20]
\w          [0-9A-Z_a-z]
\D          (?:(?:[\xC2-\xDF]|[\xE0-\xE0][\xA0-\xBF]|[\xE1-\xEC][\x80-\xBF]|[\xED-\xED][\x80-\x9F]|[\xEE-\xEF][\x80-\xBF]|[\xF0-\xF0][\x90-\xBF][\x80-\xBF]|[\xF1-\xF3][\x80-\xBF][\x80-\xBF]|[\xF4-\xF4][\x80-\x8F][\x80-\xBF])[\x00-\xFF]|[^0-9])
\S          (?:(?:[\xC2-\xDF]|[\xE0-\xE0][\xA0-\xBF]|[\xE1-\xEC][\x80-\xBF]|[\xED-\xED][\x80-\x9F]|[\xEE-\xEF][\x80-\xBF]|[\xF0-\xF0][\x90-\xBF][\x80-\xBF]|[\xF1-\xF3][\x80-\xBF][\x80-\xBF]|[\xF4-\xF4][\x80-\x8F][\x80-\xBF])[\x00-\xFF]|[^\x09\x0A\x0C\x0D\x20])
\W          (?:(?:[\xC2-\xDF]|[\xE0-\xE0][\xA0-\xBF]|[\xE1-\xEC][\x80-\xBF]|[\xED-\xED][\x80-\x9F]|[\xEE-\xEF][\x80-\xBF]|[\xF0-\xF0][\x90-\xBF][\x80-\xBF]|[\xF1-\xF3][\x80-\xBF][\x80-\xBF]|[\xF4-\xF4][\x80-\x8F][\x80-\xBF])[\x00-\xFF]|[^0-9A-Z_a-z])
\h          [\x09\x20]
\v          [\x0C\x0A\x0D]
\H          (?:(?:[\xC2-\xDF]|[\xE0-\xE0][\xA0-\xBF]|[\xE1-\xEC][\x80-\xBF]|[\xED-\xED][\x80-\x9F]|[\xEE-\xEF][\x80-\xBF]|[\xF0-\xF0][\x90-\xBF][\x80-\xBF]|[\xF1-\xF3][\x80-\xBF][\x80-\xBF]|[\xF4-\xF4][\x80-\x8F][\x80-\xBF])[\x00-\xFF]|[^\x09\x20])
\V          (?:(?:[\xC2-\xDF]|[\xE0-\xE0][\xA0-\xBF]|[\xE1-\xEC][\x80-\xBF]|[\xED-\xED][\x80-\x9F]|[\xEE-\xEF][\x80-\xBF]|[\xF0-\xF0][\x90-\xBF][\x80-\xBF]|[\xF1-\xF3][\x80-\xBF][\x80-\xBF]|[\xF4-\xF4][\x80-\x8F][\x80-\xBF])[\x00-\xFF]|[^\x0C\x0A\x0D])
---------------------------------------------------------------------------

Also \b and \B are redefined as follows to backward compatibility.

---------------------------------------------------------------------------
Before      After
---------------------------------------------------------------------------
\b          (?:\A(?=[0-9A-Z_a-z])|(?<=[\x00-\x2F\x40\x5B-\x5E\x60\x7B-\xFF])(?=[0-9A-Z_a-z])|(?<=[0-9A-Z_a-z])(?=[\x00-\x2F\x40\x5B-\x5E\x60\x7B-\xFF]|\z))
\B          (?:(?<=[0-9A-Z_a-z])(?=[0-9A-Z_a-z])|(?<=[\x00-\x2F\x40\x5B-\x5E\x60\x7B-\xFF])(?=[\x00-\x2F\x40\x5B-\x5E\x60\x7B-\xFF]))
---------------------------------------------------------------------------

Escaping Built-in Functions (UTF2.pm and Eutf2.pm provide)

Insert 'Eutf2::' at head of function name. Eutf2.pm provides your script Eutf2::* functions.

---------------------------------
Before      After
---------------------------------
length      length
substr      substr
pos         pos
split       Eutf2::split
tr///       Eutf2::tr
tr///b      tr///
tr///B      tr///
y///        Eutf2::tr
y///b       tr///
y///B       tr///
chop        Eutf2::chop
chr         Eutf2::chr
glob        Eutf2::glob
---------------------------------

------------------------------------------------------------------------------------------------------------------------
Before                   After
------------------------------------------------------------------------------------------------------------------------
use Perl::Module;        BEGIN { require 'Perl/Module.pm'; Perl::Module->import() if Perl::Module->can('import'); }
use Perl::Module @list;  BEGIN { require 'Perl/Module.pm'; Perl::Module->import(@list) if Perl::Module->can('import'); }
use Perl::Module ();     BEGIN { require 'Perl/Module.pm'; }
no Perl::Module;         BEGIN { require 'Perl/Module.pm'; Perl::Module->unimport() if Perl::Module->can('unimport'); }
no Perl::Module @list;   BEGIN { require 'Perl/Module.pm'; Perl::Module->unimport(@list) if Perl::Module->can('unimport'); }
no Perl::Module ();      BEGIN { require 'Perl/Module.pm'; }
------------------------------------------------------------------------------------------------------------------------

Un-Escaping bytes::* Functions (UTF2.pm provides)

UTF2.pm remove 'bytes::' at head of function name.

------------------------------------
Before           After
------------------------------------
bytes::chr       chr
bytes::index     index
bytes::length    length
bytes::ord       ord
bytes::rindex    rindex
bytes::substr    substr
------------------------------------

Escaping Function Name (You do)

You need write 'UTF2::' at head of function name when you want character oriented function. See 'CHARACTER ORIENTED FUNCTIONS'.

---------------------------------
Before      After
---------------------------------
ord         UTF2::ord
reverse     UTF2::reverse
length      UTF2::length
substr      UTF2::substr
index       UTF2::index
rindex      UTF2::rindex
---------------------------------

Escaping Built-in Standard Module (Eutf2.pm provides)

Eutf2.pm does "BEGIN { unshift @INC, '/Perl/site/lib/UTF2' }" at head. Store the standard module modified for UTF2 software in this directory to override built-in standard modules.

Escaping Standard Module Content (You do)

You need copy built-in standard module to /Perl/site/lib/UTF2 and change 'use utf8;' to 'use UTF2;' in its. You need help yourself for now.

Back to and see 'Escaping Your Script'. Enjoy hacking!!

CHARACTER ORIENTED FUNCTIONS

Order of Character

$ord = UTF2::ord($string);

This function returns the numeric value (ASCII or UTF-2) of the first character
of $string. The return value is always unsigned.

Reverse list or string

@reverse = UTF2::reverse(@list);
$reverse = UTF2::reverse(@list);

In list context, this function returns a list value consisting of the elements of
@list in the opposite order. The function can be used to create descending
sequences:

for (UTF2::reverse(1 .. 10)) { ... }

Because of the way hashes flatten into lists when passed as a @list, reverse can
also be used to invert a hash, presuming the values are unique:

%barfoo = UTF2::reverse(%foobar);

In scalar context, the function concatenates all the elements of LIST and then
returns the reverse of that resulting string, character by character.

length by UTF-2 character

$length = UTF2::length($string);
$length = UTF2::length();

This function returns the length in characters of the scalar value $string. If
$string is omitted, it returns the UTF2::length of $_.

Do not try to use length to find the size of an array or hash. Use scalar @array
for the size of an array, and scalar keys %hash for the number of key/value pairs
in a hash. (The scalar is typically omitted when redundant.)

To find the length of a string in bytes rather than characters, say:

$blen = length($string);
$blen = CORE::length($string);
$blen = bytes::length($string);

substr by UTF-2 character

$substr = UTF2::substr($string,$offset,$length,$replacement);
$substr = UTF2::substr($string,$offset,$length);
$substr = UTF2::substr($string,$offset);

This function extracts a substring out of the string given by $string and returns
it. The substring is extracted starting at $offset characters from the front of
the string.
If $offset is negative, the substring starts that far from the end of the string
instead. If $length is omitted, everything to the end of the string is returned.
If $length is negative, the length is calculated to leave that many characters off
the end of the string. Otherwise, $length indicates the length of the substring to
extract, which is sort of what you'd expect.

An alternative to using UTF2::substr as an lvalue is to specify the $replacement
string as the fourth argument. This allows you to replace parts of the $string and
return what was there before in one operation, just as you can with splice. The next
example also replaces the last character of $var with "Curly" and puts that replaced
character into $oldstr: 

$oldstr = UTF2::substr($var, -1, 1, "Curly");

If you assign something shorter than the length of your substring, the string will
shrink, and if you assign something longer than the length, the string will grow to
accommodate it. To keep the string the same length, you may need to pad or chop your
value using sprintf or the x operator. If you attempt to assign to an unallocated
area past the end of the string, UTF2::substr raises an exception.

To prepend the string "Larry" to the current value of $_, use:

UTF2::substr($var, 0, 0, "Larry");

To instead replace the first character of $_ with "Moe", use:

UTF2::substr($var, 0, 1, "Moe");

And finally, to replace the last character of $var with "Curly", use:

UTF2::substr($var, -1, 1, "Curly");

index by UTF-2 character

$index = UTF2::index($string,$substring,$offset);
$index = UTF2::index($string,$substring);

This function searches for one string within another. It returns the position of
the first occurrence of $substring in $string. The $offset, if specified, says how
many characters from the start to skip before beginning to look. Positions are
based at 0. If the substring is not found, the function returns one less than the
base, ordinarily -1. To work your way through a string, you might say:

$pos = -1;
while (($pos = UTF2::index($string, $lookfor, $pos)) > -1) {
    print "Found at $pos\n";
    $pos++;
}

rindex by UTF-2 character

$rindex = UTF2::rindex($string,$substring,$position);
$rindex = UTF2::rindex($string,$substring);

This function works just like UTF2::index except that it returns the position of
the last occurrence of $substring in $string (a reverse index). The function
returns -1 if not $substring is found. $position, if specified, is the rightmost
position that may be returned. To work your way through a string backward, say:

$pos = UTF2::length($string);
while (($pos = UTF2::rindex($string, $lookfor, $pos)) >= 0) {
    print "Found at $pos\n";
    $pos--;
}

Perl5.6 Emulation on perl5.005

To be compatible with Perl5.6 on perl5.005, script is converted as follows.

--------------------------------------------------------------------
Before          After                  in BEGIN { } of Eutf2.pm
--------------------------------------------------------------------
binmode(...);   Eutf2::binmode(...);   *CORE::GLOBAL::binmode = ...
open(...);      Eutf2::open(...);      *CORE::GLOBAL::open    = ...
--------------------------------------------------------------------

Ignore utf8 pragma

Comment out pragma to ignore utf8 environment, and Eutf2.pm provides these
functions.

---------------------------------------------------------------------
Before          After                  Explanation
---------------------------------------------------------------------
use utf8;       # use utf8;            Eutf2.pm provides utf8::*
no utf8;        # no utf8;             functions even if 'no utf8;'
use bytes;      # use bytes;           Eutf2.pm provides bytes::*
no bytes;       # no bytes;            functions even if 'no bytes;'
---------------------------------------------------------------------

binmode (Perl5.6 emulation on perl5.005)

binmode(FILEHANDLE, $disciplines);
binmode(FILEHANDLE);
binmode($filehandle, $disciplines);
binmode($filehandle);

* two arguments

If you are using perl5.005, UTF2 software emulate perl5.6's binmode function.
Only the point is here. See also perlfunc/binmode for details.

This function arranges for the FILEHANDLE to have the semantics specified by the
$disciplines argument. If $disciplines is omitted, ':raw' semantics are applied
to the filehandle. If FILEHANDLE is an expression, the value is taken as the
name of the filehandle or a reference to a filehandle, as appropriate.
The binmode function should be called after the open but before any I/O is done
on the filehandle. The only way to reset the mode on a filehandle is to reopen
the file, since the various disciplines may have treasured up various bits and
pieces of data in various buffers.

The ":raw" discipline tells Perl to keep its cotton-pickin' hands off the data.
For more on how disciplines work, see the open function.

open (Perl5.6 emulation on perl5.005)

open(FILEHANDLE, $mode, $expr);
open(FILEHANDLE, $expr);
open(FILEHANDLE);
open(my $filehandle, $mode, $expr);
open(my $filehandle, $expr);
open(my $filehandle);

* autovivification filehandle
* three arguments

If you are using perl5.005, UTF2 software emulate perl5.6's open function.
Only the point is here. See also perlfunc/open for details.

As that example shows, the FILEHANDLE argument is often just a simple identifier
(normally uppercase), but it may also be an expression whose value provides a
reference to the actual filehandle. (The reference may be either a symbolic
reference to the filehandle name or a hard reference to any object that can be
interpreted as a filehandle.) This is called an indirect filehandle, and any
function that takes a FILEHANDLE as its first argument can handle indirect
filehandles as well as direct ones. But open is special in that if you supply
it with an undefined variable for the indirect filehandle, Perl will automatically
define that variable for you, that is, autovivifying it to contain a proper
filehandle reference.

{
    my $fh;                   # (uninitialized)
    open($fh, ">logfile")     # $fh is autovivified
        or die "Can't create logfile: $!";
        ...                   # do stuff with $fh
}                             # $fh closed here

The my $fh declaration can be readably incorporated into the open:

open my $fh, ">logfile" or die ...

The > symbol you've been seeing in front of the filename is an example of a mode.
Historically, the two-argument form of open came first. The recent addition of
the three-argument form lets you separate the mode from the filename, which has
the advantage of avoiding any possible confusion between the two. In the following
example, we know that the user is not trying to open a filename that happens to
start with ">". We can be sure that they're specifying a $mode of ">", which opens
the file named in $expr for writing, creating the file if it doesn't exist and
truncating the file down to nothing if it already exists:

open(LOG, ">", "logfile")  or die "Can't create logfile: $!";

With the one- or two-argument form of open, you have to be careful when you use
a string variable as a filename, since the variable may contain arbitrarily
weird characters (particularly when the filename has been supplied by arbitrarily
weird characters on the Internet). If you're not careful, parts of the filename
might get interpreted as a $mode string, ignorable whitespace, a dup specification,
or a minus.
Here's one historically interesting way to insulate yourself:

$path =~ s#^([ ])#./$1#;
open (FH, "< $path\0") or die "can't open $path: $!";

But that's still broken in several ways. Instead, just use the three-argument
form of open to open any arbitrary filename cleanly and without any (extra)
security risks:

open(FH, "<", $path) or die "can't open $path: $!";

As of the 5.6 release of Perl, you can specify binary mode in the open function
without a separate call to binmode. As part of the $mode
argument (but only in the three-argument form), you may specify various input
and output disciplines.
To do the equivalent of a binmode, use the three argument form of open and stuff
a discipline of :raw in after the other $mode characters:

open(FH, "<:raw", $path) or die "can't open $path: $!";

Table 1. I/O Disciplines
-------------------------------------------------
Discipline      Meaning
-------------------------------------------------
:raw            Binary mode; do no processing
:crlf           Text mode; Intuit newlines
:encoding(...)  Legacy encoding
-------------------------------------------------

You'll be able to stack disciplines that make sense to stack, so, for instance,
you could say:

open(FH, "<:crlf:encoding(UTF2)", $path) or die "can't open $path: $!";

dummy utf8::upgrade

$num_octets = utf8::upgrade($string);

Returns the number of octets necessary to represent the string.

dummy utf8::downgrade

$success = utf8::downgrade($string[, FAIL_OK]);

Returns true always.

dummy utf8::encode

utf8::encode($string);

Returns nothing.

dummy utf8::decode

$success = utf8::decode($string);

Returns true always.

dummy utf8::is_utf8

$flag = utf8::is_utf8(STRING);

Returns false always.

dummy utf8::valid

$flag = utf8::valid(STRING);

Returns true always.

dummy bytes::chr

This function is same as chr.

dummy bytes::index

This function is same as index.

dummy bytes::length

This function is same as length.

dummy bytes::ord

This function is same as ord.

dummy bytes::rindex

This function is same as rindex.

dummy bytes::substr

This function is same as substr.

ENVIRONMENT VARIABLE

This software uses the flock function for exclusive control. The execution of the
program is blocked until it becomes possible to read or write the file.
You can have it not block in the flock function by defining environment variable
SJIS_NONBLOCK.

Example:

  SET SJIS_NONBLOCK=1

(The value '1' doesn't have the meaning)

BUGS AND LIMITATIONS

Please patches and report problems to author are welcome.

format

Function "format" can't handle multiple octet code same as original Perl.
UTF2::substr as lvalue

UTF2::substr differs from CORE::substr, and cannot be used as a lvalue. To change part of a string, you can use the optional fourth argument which is the replacement string.

UTF2::substr($string, 13, 4, "JPerl");

AUTHOR

INABA Hitoshi <ina@cpan.org>

This project was originated by INABA Hitoshi.

LICENSE AND COPYRIGHT

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

This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

MY GOAL

P.401 See chapter 15: Unicode of ISBN 0-596-00027-8 Programming Perl Third Edition.

Before the introduction of Unicode support in perl, The eq operator just compared the byte-strings represented by two scalars. Beginning with perl 5.8, eq compares two byte-strings with simultaneous consideration of the UTF8 flag.

 Information processing model beginning with perl 5.8

   +----------------------+---------------------+
   |     Text strings     |                     |
   +----------+-----------|    Binary strings   |
   |   UTF8   |  Latin-1  |                     |
   +----------+-----------+---------------------+
   | UTF8     |            Not UTF8             |
   | Flagged  |            Flagged              |
   +--------------------------------------------+
   http://perl-users.jp/articles/advent-calendar/2010/casual/4

   You should memorize this figure.

   (Why is only Latin-1 special?)

This change consequentially made a big gap between a past script and new script. Both scripts cannot re-use the code mutually any longer. Because a new method puts a strain in the programmer, it will still take time to replace all the in existence scripts.

The biggest problem of new method is that the UTF8 flag can't synchronize to real encode of string. Thus you must debug about UTF8 flag, before your script. How to solve it by returning to a past method, I will quote page 402 of Programming Perl, 3rd ed. again.

 Information processing model beginning with this software

   +-----------------------------------+
   |           Octet Strings           | aka Binary strings
   +-----------------------------------+
   |         Character Strings         | aka Text strings
   +-----------------------------------+
   |      ASCII Compatible Encoding    | ex. UTF-2
   +-----------------------------------+
               (No UTF8 Flag)

   You need not memorize this figure.

Ideally, I'd like to achieve these five Goals:

Goal #1:

Old byte-oriented programs should not spontaneously break on the old byte-oriented data they used to work on.

It has already been achieved by UTF-2 designed for combining with old byte-oriented ASCII.

Goal #2:

Old byte-oriented programs should magically start working on the new character-oriented data when appropriate.

Still now, 1 octet is counted with 1 by embedded functions length, substr, index, rindex and pos that handle length and position of string. In this part, there is no change. The length of 1 character of 2 octet code is 2.

On the other hand, the regular expression in the script is added the multibyte anchoring processing with this software, instead of you.

figure of Goal #1 and Goal #2.

                         GOAL#1  GOAL#2
                  (a)     (b)     (c)     (d)     (e)
+--------------+-------+-------+-------+-------+-------+
| data         |  Old  |  Old  |  New  |  Old  |  New  |
+--------------+-------+-------+-------+-------+-------+
| script       |  Old  |      Old      |      New      |
+--------------+-------+---------------+---------------+
| interpreter  |  Old  |              New              |
+--------------+-------+-------------------------------+
Old --- Old byte-oriented
New --- New character-oriented

There is a combination from (a) to (e) in data, script and interpreter of old and new. Let's add the Encode module and this software did not exist at time of be written this document and JPerl did exist.

                  (a)     (b)     (c)     (d)     (e)
                                JPerl           Encode,UTF2
+--------------+-------+-------+-------+-------+-------+
| data         |  Old  |  Old  |  New  |  Old  |  New  |
+--------------+-------+-------+-------+-------+-------+
| script       |  Old  |      Old      |      New      |
+--------------+-------+---------------+---------------+
| interpreter  |  Old  |              New              |
+--------------+-------+-------------------------------+
Old --- Old byte-oriented
New --- New character-oriented

The reason why JPerl is very excellent is that it is at the position of (c). That is, it is not necessary to do a special description to the script to process new character-oriented string.

Contrasting is Encode module and describing "use UTF2;" on this software, in this case, a new description is necessary.

Goal #3:

Programs should run just as fast in the new character-oriented mode as in the old byte-oriented mode.

It is impossible. Because the following time is necessary.

(1) Time of escape script for old byte-oriented perl.

Goal #4:

Perl should remain one language, rather than forking into a byte-oriented Perl and a character-oriented Perl.

JPerl forked the perl interpreter so as not to fork the Perl language. But the Perl core team might not hope for the perl interpreter's fork. As a result, the Perl language forked, and the community was reduced through necessity.

A character-oriented perl is not necessary to make it specially, because a byte-oriented perl can already treat the binary data. This software is only an application program of Perl, a filter program. If perl can be executed, this software will be able to be executed.

And you will get support from the Perl community, when you solve the problem by the Perl script.

Goal #5:

JPerl users will be able to maintain JPerl by Perl. Or MacJPerl users will be able to maintain MacJPerl by MacPerl.

May the JPerl be with you, always.

Back when Programming Perl, 3rd ed. was written, UTF8 flag was not born and Perl is designed to make the easy jobs easy. This software provide programming environment like at that time.

ACKNOWLEDGEMENTS

This software was made referring to software and the document that the following hackers or persons had made. I am thankful to all persons.

Rick Yamashita, Shift_JIS
ttp://furukawablog.spaces.live.com/Blog/cns!1pmWgsL289nm7Shn7cS0jHzA!2225.entry
(add 'h' at head)

Larry Wall, Perl
http://www.perl.org/

Kazumasa Utashiro, jcode.pl
ftp://ftp.iij.ad.jp/pub/IIJ/dist/utashiro/perl/

Jeffrey E. F. Friedl, Mastering Regular Expressions
http://www.oreilly.com/catalog/regex/index.html

SADAHIRO Tomoyuki, The right way of using Shift_JIS
http://homepage1.nifty.com/nomenclator/perl/shiftjis.htm
http://search.cpan.org/dist/UTF-2-Regexp/

Yukihiro "Matz" Matsumoto, YAPC::Asia2006 Ruby on Perl(s)
http://www.rubyist.net/~matz/slides/yapc2006/

jscripter, For jperl users
http://homepage1.nifty.com/kazuf/jperl.html

Bruce., Unicode in Perl
http://www.rakunet.org/TSNET/TSabc/18/546.html

Hiroaki Izumi, Perl5.8/Perl5.10 is not useful on the Windows.
http://www.aritia.jp/hizumi/oldtext/perlwin.html

TSUKAMOTO Makio, Perl memo/file path of Windows
http://digit.que.ne.jp/work/wiki.cgi?Perl%E3%83%A1%E3%83%A2%2FWindows%E3%81%A7%E3%81%AE%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB%E3%83%91%E3%82%B9

chaichanPaPa, Matching Shift_JIS file name
http://d.hatena.ne.jp/chaichanPaPa/20080802/1217660826

SUZUKI Norio, Jperl
http://homepage2.nifty.com/kipp/perl/jperl/

WATANABE Hirofumi, Jperl
http://search.cpan.org/~watanabe/
ftp://ftp.oreilly.co.jp/pcjp98/watanabe/jperlconf.ppt

Chuck Houpt, Michiko Nozu, MacJPerl
http://habilis.net/macjperl/index.j.html

Kenichi Ishigaki, Pod-PerldocJp, Welcome to modern Perl world
http://search.cpan.org/dist/Pod-PerldocJp/
http://gihyo.jp/dev/serial/01/modern-perl/0031
http://gihyo.jp/dev/serial/01/modern-perl/0032
http://gihyo.jp/dev/serial/01/modern-perl/0033

Dan Kogai, Encode module
http://search.cpan.org/dist/Encode/
http://www.dan.co.jp/~dankogai/yapcasia2006/slide.html

Juerd, Perl Unicode Advice
http://juerd.nl/site.plp/perluniadvice

daily dayflower, 2008-06-25 perluniadvice
http://d.hatena.ne.jp/dayflower/20080625/1214374293

Jesse Vincent, Compatibility is a virtue
http://www.nntp.perl.org/group/perl.perl5.porters/2010/05/msg159825.html

Tokyo-pm archive
http://mail.pm.org/pipermail/tokyo-pm/
http://mail.pm.org/pipermail/tokyo-pm/1999-September/001844.html
http://mail.pm.org/pipermail/tokyo-pm/1999-September/001854.html

ruby-list
http://blade.nagaokaut.ac.jp/ruby/ruby-list/index.shtml
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/2440
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/2446
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/2569
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/9427
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/9431
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/10500
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/10501
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/10502
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/12385
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/12392
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/12393
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/19156

To install UTF2, copy and paste the appropriate command in to your terminal.

cpanm

cpanm UTF2

CPAN shell

perl -MCPAN -e shell
install UTF2

For more information on module installation, please visit the detailed CPAN module installation guide.

	Global
`s`	Focus search bar
`?`	Bring up this help dialog

	GitHub
`g` `p`	Go to pull requests
`g` `i`	go to github issues (only if github is preferred repository)

	POD
`g` `a`	Go to author
`g` `c`	Go to changes
`g` `i`	Go to issues
`g` `d`	Go to dist
`g` `r`	Go to repository/SCM
`g` `s`	Go to source
`g` `b`	Go to file browse

	Search terms
module: (e.g. module:Plugin)
distribution: (e.g. distribution:Dancer auth)
author: (e.g. author:SONGMU Redis)
version: (e.g. version:1.00)