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[p5sagit/p5-mst-13.2.git] / ext / Encode / lib / Encode / Supported.pod

=head1 NAME

Encode::Supported -- Supported encodings by Encode

=head1 DESCRIPTION

=head2 Encoding Names

Encoding names are case insensitive. White space in names
is ignored.  In addition an encoding may have aliases.
Each encoding has one "canonical" name.  The "canonical"
name is chosen from the names of the encoding by picking
he first in the following sequence:

       o The MIME name as defined in IETF RFCs.
       o The name in the IANA registry.
       o The name used by the organization that defined it.

Because of all the alias issues, and because in the general case 
encodings have state, "Encode" uses the encoding object internally 
once an operation is in progress.

=head1 Supported Encodings

As of Perl 5.8.0, at least the following encodings are recognized.
Note that unless otherwise specified, they are all case insensitive
(via alias) and all occurance of spaces are replaced with '-'.  In
other words, "ISO 8859 1" and "iso-8859-1" are identical.

Encodings are categorized and implemented in several different modules
but you don't have to C<use Encode::XX> to make them available for
most cases.  Encode.pm will automatically load those modules in need.

=head2 Built-in Encodings

The following encodings are always available.

  Canonical	Aliases
  -----------------------
  iso-8859-1	latin1
  US-ascii	ascii
  UCS-2		ucs2, iso-10646-1
  UCS-2le
  UTF-8		utf8
  -----------------------

=head2 Encode::Byte

The following encodings are based single-byte encoding implemented as
extended ASCII.  For most cases it uses \x80-\xff (upper half) to map
non-ASCII characters.

  -----------------------
  iso-8859-1	latin
  iso-8859-2	latin2
  iso-8859-3	latin3
  iso-8859-4	latin4
  iso-8859-5	latin
  iso-8859-6	latin
  iso-8859-7
  iso-8859-8
  iso-8859-9	latin5
  iso-8859-10	latin6
  iso-8859-11
  (iso-8859-12 is nonexistent)
  iso-8859-13   latin7
  iso-8859-14	latin8
  iso-8859-15	latin9
  iso-8859-16	latin10

  koi8-f
  koi8-r
  koi8-u

  viscii	# ASCII + vietnamese

  cp1250	WinLatin2
  cp1251	WinCyrillic
  cp1252	WinLatin1
  cp1253	WinGreek
  cp1254	WinTurkiskh
  cp1255	WinHebrew
  cp1256	WinArabic
  cp1257	WinBaltic
  cp1258	WinVietnamese
  # all cp* are also available as ibm-* and ms-*

  maccentraleuropean  
  maccroatian
  macroman
  maccyrillic
  macromanian
  macdingbats       
  macsami
  macgreek 
  macthai
  macicelandic    
  macturkish
  macukraine
  -----------------------

=head2 The CJK: Chinese, Japanese, Korean (Multibyte)

Note Vietnamese is listed above.  Also read "Encoding vs Charset"
below.  Also note these are impelemented in distinct module by
languages, due the the size concerns.  See these perldocs also.

=over 4

=item Encode::CN -- Continental China

  -----------------------
  cp936      gbk		    
  euc-cn
  gb12345
  gb2312
  hz
  iso-ir-165
  -----------------------

=item Encode::JP -- Japan

  -----------------------
  7bit-jis	  jis
  cp932
  euc-jp	  ujis
  iso-2022-jp
  macjapan
  shiftjis	  Shift_JIS, sjis
  -----------------------

=item Encode::KR -- Korea

  -----------------------
  euc-kr
  ksc5601
  cp949
  -----------------------

=item Encode::TW -- Taiwan

  -----------------------
  big5
  big5-hkscs
  cp950
  -----------------------

=item Encode::HanExtra -- More Chinese via CPAN

Due to size concerns, additional Chinese encodings below are
distributed separately on CPAN, under the name Encode::HanExtra.

  -----------------------
  gb18030
  euc-tw
  big5plus
  -----------------------

=back

=head2 Miscellaneous encodings

=over 4

=item Encode::EBCDIC

See perlebcdic for details.

  -----------------------
  cp1047
  cp37
  posix-bc
  -----------------------

=item Enocode::Symbols

For symbols  and dingbats.

  -----------------------
  symbol
  dingbats
  -----------------------

=back

=head1 Encoding vs. Charset

Character encoding (or just "encoding") and Character Set (or just
"charset") are often used interchangeably but they are different
concepts.

Charset determines which characters to be included in a given text.

Encoding actually maps charset(s) to stream of bits.

Note a given encoding contains multiple charsets.  For instance,
euc-jp contains ASCII, JIS X 0201 (Hankaku Kana), JIS X 0208 (Zenkaku
Kana and Kanji) and JIS X 0212 (Extended Kanji) in a single encoding.

As the name suggests, the Encode module supports encodings, not
individual charsets.

=head1 Encoding Classification (by Anton Tagunov)

Encodings

  US-ASCII    UTF-8       KOI8-R      ISO-8859-*
  ISO-2022-CN ISO-2022-JP Big5
  EUC-CN      EUC-JP      EUC-KR

are <http://www.iana.org/assignments/character-sets>-registered as
preferred MIME names and may probably be used  over the Internet.  So is

  Shift_JIS

but despite its wide spread it bears the label of being
Microsft proprietary -- was.  Now Shift JIS is official as of
JIS X 0208-1997.

         UTF-16 KOI8-U

are IANA-registered preferred MIME names but probably
shoule be avoided as encoding for web pages due to lack of
browser support.

  ISO-2022      (http://www.ecma.ch/ecma1/STAND/ECMA-035.HTM)
  ISO-2022-JP-1 (http://www.faqs.org/rfcs/rfc2237.html)
  ISO-IR-165    (http://www.faqs.org/rfcs/rfc1345.html)
  GBK
  VISCII
  GB 12345      (only plains 1 and 2 available)
  GB 18030
  CNS 11643

are totally valid encodings but not registered at IANA.

   BIG5PLUS
   EUC-JP-0212   (Encode::lib::Encode::Tcl::Extended)

are a bit proprietary

You may probably get some info on CJK encodings at

brief description for most of the mentioned CJK encodings

F<http://www.debian.org.ru/doc/manuals/intro-i18n/ch-codes.html>

several years old, but still useful

F<http://www.oreilly.com/people/authors/lunde/cjk_inf.html>

and some in-depth reading for the heroes :-)
F<http://www.ecma.ch/ecma1/STAND/ECMA-035.HTM> (eq ISO-2022)

=head1 See Also

L<Encode>, 
L<Encode::Byte>, 
L<Encode::CN>, L<Encode::JP>, L<Encode::KR>, L<Encode::TW>
L<Encode::EBCDIC>, L<Encode::Symbol>

=cut