1 # $Id: encoding.pm,v 2.12 2013/04/26 18:30:46 dankogai Exp $
3 our $VERSION = sprintf "%d.%02d", q$Revision: 2.12 $ =~ /(\d+)/g;
9 use constant DEBUG => !!$ENV{PERL_ENCODE_DEBUG};
12 if ( ord("A") == 193 ) {
14 Carp::croak("encoding: pragma does not support EBCDIC platforms");
19 eval { require PerlIO::encoding };
21 $HAS_PERLIO = ( PerlIO::encoding->VERSION >= 0.02 );
26 $] > 5.008 and return 0; # 5.8.1 or higher then no
27 my %utfs = map { $_ => 1 }
28 qw(utf8 UCS-2BE UCS-2LE UTF-16 UTF-16BE UTF-16LE
29 UTF-32 UTF-32BE UTF-32LE);
30 $utfs{$name} or return 0; # UTFs or no
34 return $Config{perl_patchlevel} ? 0 : 1 # maintperl then no
37 sub in_locale { $^H & ( $locale::hint_bits || 0 ) }
39 sub _get_locale_encoding {
42 # I18N::Langinfo isn't available everywhere
44 require I18N::Langinfo;
45 I18N::Langinfo->import(qw(langinfo CODESET));
46 $locale_encoding = langinfo( CODESET() );
51 no warnings 'uninitialized';
53 if ( (not $locale_encoding) && in_locale() ) {
54 if ( $ENV{LC_ALL} =~ /^([^.]+)\.([^.@]+)(@.*)?$/ ) {
55 ( $country_language, $locale_encoding ) = ( $1, $2 );
57 elsif ( $ENV{LANG} =~ /^([^.]+)\.([^.@]+)(@.*)?$/ ) {
58 ( $country_language, $locale_encoding ) = ( $1, $2 );
61 # LANGUAGE affects only LC_MESSAGES only on glibc
63 elsif ( not $locale_encoding ) {
64 if ( $ENV{LC_ALL} =~ /\butf-?8\b/i
65 || $ENV{LANG} =~ /\butf-?8\b/i )
67 $locale_encoding = 'utf8';
70 # Could do more heuristics based on the country and language
71 # parts of LC_ALL and LANG (the parts before the dot (if any)),
72 # since we have Locale::Country and Locale::Language available.
73 # TODO: get a database of Language -> Encoding mappings
74 # (the Estonian database at http://www.eki.ee/letter/
75 # would be excellent!) --jhi
77 if ( defined $locale_encoding
78 && lc($locale_encoding) eq 'euc'
79 && defined $country_language )
81 if ( $country_language =~ /^ja_JP|japan(?:ese)?$/i ) {
82 $locale_encoding = 'euc-jp';
84 elsif ( $country_language =~ /^ko_KR|korean?$/i ) {
85 $locale_encoding = 'euc-kr';
87 elsif ( $country_language =~ /^zh_CN|chin(?:a|ese)$/i ) {
88 $locale_encoding = 'euc-cn';
90 elsif ( $country_language =~ /^zh_TW|taiwan(?:ese)?$/i ) {
91 $locale_encoding = 'euc-tw';
96 "encoding: Locale encoding '$locale_encoding' too ambiguous"
101 return $locale_encoding;
106 Carp::croak("encoding: pragma has been removed");
109 warnings::warnif("deprecated",
110 "Use of the encoding pragma is deprecated")
116 Carp::croak("encoding: no encoding specified.");
118 if ( $name eq ':_get_locale_encoding' ) { # used by lib/open.pm
119 my $caller = caller();
122 *{"${caller}::_get_locale_encoding"} = \&_get_locale_encoding;
126 $name = _get_locale_encoding() if $name eq ':locale';
128 $name = $ENV{PERL_ENCODING} unless defined $name;
129 my $enc = find_encoding($name);
130 unless ( defined $enc ) {
132 Carp::croak("encoding: Unknown encoding '$name'");
134 $name = $enc->name; # canonize
135 unless ( $arg{Filter} ) {
136 DEBUG and warn "_exception($name) = ", _exception($name);
137 _exception($name) or ${^ENCODING} = $enc;
138 $HAS_PERLIO or return 1;
141 defined( ${^ENCODING} ) and undef ${^ENCODING};
143 # implicitly 'use utf8'
144 require utf8; # to fetch $utf8::hint_bits;
145 $^H |= $utf8::hint_bits;
147 require Filter::Util::Call;
148 Filter::Util::Call->import;
151 my $status = filter_read();
153 $_ = $enc->decode( $_, 1 );
160 $@ eq '' and DEBUG and warn "Filter installed";
162 defined ${^UNICODE} and ${^UNICODE} != 0 and return 1;
163 for my $h (qw(STDIN STDOUT)) {
165 unless ( defined find_encoding( $arg{$h} ) ) {
168 "encoding: Unknown encoding for $h, '$arg{$h}'");
170 eval { binmode( $h, ":raw :encoding($arg{$h})" ) };
173 unless ( exists $arg{$h} ) {
175 no warnings 'uninitialized';
176 binmode( $h, ":raw :encoding($name)" );
185 return 1; # I doubt if we need it, though
192 binmode( STDIN, ":raw" );
193 binmode( STDOUT, ":raw" );
199 if ( $INC{"Filter/Util/Call.pm"} ) {
200 eval { filter_del() };
211 encoding - allows you to write your script in non-ascii or non-utf8
215 This module is deprecated under perl 5.18. It uses a mechanism provided by
216 perl that is deprecated under 5.18 and higher, and may be removed in a
219 The easiest and the best alternative is to write your script in UTF-8
222 use utf8; # not use encoding ':utf8';
224 See L<perluniintro> and L<utf8> for details.
228 use encoding "greek"; # Perl like Greek to you?
229 use encoding "euc-jp"; # Jperl!
231 # or you can even do this if your shell supports your native encoding
233 perl -Mencoding=latin2 -e'...' # Feeling centrally European?
234 perl -Mencoding=euc-kr -e'...' # Or Korean?
238 # A simple euc-cn => utf-8 converter
239 use encoding "euc-cn", STDOUT => "utf8"; while(<>){print};
241 # "no encoding;" supported (but not scoped!)
244 # an alternate way, Filter
245 use encoding "euc-jp", Filter=>1;
246 # now you can use kanji identifiers -- in euc-jp!
249 # note that this probably means that unless you have a complete control
250 # over the environments the application is ever going to be run, you should
251 # NOT use the feature of encoding pragma allowing you to write your script
252 # in any recognized encoding because changing locale settings will wreck
253 # the script; you can of course still use the other features of the pragma.
254 use encoding ':locale';
258 Let's start with a bit of history: Perl 5.6.0 introduced Unicode
259 support. You could apply C<substr()> and regexes even to complex CJK
260 characters -- so long as the script was written in UTF-8. But back
261 then, text editors that supported UTF-8 were still rare and many users
262 instead chose to write scripts in legacy encodings, giving up a whole
263 new feature of Perl 5.6.
265 Rewind to the future: starting from perl 5.8.0 with the B<encoding>
266 pragma, you can write your script in any encoding you like (so long
267 as the C<Encode> module supports it) and still enjoy Unicode support.
268 This pragma achieves that by doing the following:
274 Internally converts all literals (C<q//,qq//,qr//,qw///, qx//>) from
275 the encoding specified to utf8. In Perl 5.8.1 and later, literals in
276 C<tr///> and C<DATA> pseudo-filehandle are also converted.
280 Changing PerlIO layers of C<STDIN> and C<STDOUT> to the encoding
285 =head2 Literal Conversions
287 You can write code in EUC-JP as follows:
289 my $Rakuda = "\xF1\xD1\xF1\xCC"; # Camel in Kanji
290 #<-char-><-char-> # 4 octets
291 s/\bCamel\b/$Rakuda/;
293 And with C<use encoding "euc-jp"> in effect, it is the same thing as
296 my $Rakuda = "\x{99F1}\x{99DD}"; # two Unicode Characters
297 s/\bCamel\b/$Rakuda/;
299 =head2 PerlIO layers for C<STD(IN|OUT)>
301 The B<encoding> pragma also modifies the filehandle layers of
302 STDIN and STDOUT to the specified encoding. Therefore,
304 use encoding "euc-jp";
305 my $message = "Camel is the symbol of perl.\n";
306 my $Rakuda = "\xF1\xD1\xF1\xCC"; # Camel in Kanji
307 $message =~ s/\bCamel\b/$Rakuda/;
310 Will print "\xF1\xD1\xF1\xCC is the symbol of perl.\n",
311 not "\x{99F1}\x{99DD} is the symbol of perl.\n".
313 You can override this by giving extra arguments; see below.
315 =head2 Implicit upgrading for byte strings
317 By default, if strings operating under byte semantics and strings
318 with Unicode character data are concatenated, the new string will
319 be created by decoding the byte strings as I<ISO 8859-1 (Latin-1)>.
321 The B<encoding> pragma changes this to use the specified encoding
322 instead. For example:
325 my $string = chr(20000); # a Unicode string
326 utf8::encode($string); # now it's a UTF-8 encoded byte string
327 # concatenate with another Unicode string
328 print length($string . chr(20000));
330 Will print C<2>, because C<$string> is upgraded as UTF-8. Without
331 C<use encoding 'utf8';>, it will print C<4> instead, since C<$string>
332 is three octets when interpreted as Latin-1.
336 If the C<encoding> pragma is in scope then the lengths returned are
337 calculated from the length of C<$/> in Unicode characters, which is not
338 always the same as the length of C<$/> in the native encoding.
340 This pragma affects utf8::upgrade, but not utf8::downgrade.
342 =head1 FEATURES THAT REQUIRE 5.8.1
344 Some of the features offered by this pragma requires perl 5.8.1. Most
345 of these are done by Inaba Hiroto. Any other features and changes
350 =item "NON-EUC" doublebyte encodings
352 Because perl needs to parse script before applying this pragma, such
353 encodings as Shift_JIS and Big-5 that may contain '\' (BACKSLASH;
354 \x5c) in the second byte fails because the second byte may
355 accidentally escape the quoting character that follows. Perl 5.8.1
356 or later fixes this problem.
360 C<tr//> was overlooked by Perl 5 porters when they released perl 5.8.0
361 See the section below for details.
363 =item DATA pseudo-filehandle
365 Another feature that was overlooked was C<DATA>.
373 =item use encoding [I<ENCNAME>] ;
375 Sets the script encoding to I<ENCNAME>. And unless ${^UNICODE}
376 exists and non-zero, PerlIO layers of STDIN and STDOUT are set to
377 ":encoding(I<ENCNAME>)".
379 Note that STDERR WILL NOT be changed.
381 Also note that non-STD file handles remain unaffected. Use C<use
382 open> or C<binmode> to change layers of those.
384 If no encoding is specified, the environment variable L<PERL_ENCODING>
385 is consulted. If no encoding can be found, the error C<Unknown encoding
386 'I<ENCNAME>'> will be thrown.
388 =item use encoding I<ENCNAME> [ STDIN =E<gt> I<ENCNAME_IN> ...] ;
390 You can also individually set encodings of STDIN and STDOUT via the
391 C<< STDIN => I<ENCNAME> >> form. In this case, you cannot omit the
392 first I<ENCNAME>. C<< STDIN => undef >> turns the IO transcoding
395 When ${^UNICODE} exists and non-zero, these options will completely
396 ignored. ${^UNICODE} is a variable introduced in perl 5.8.1. See
397 L<perlrun> see L<perlvar/"${^UNICODE}"> and L<perlrun/"-C"> for
398 details (perl 5.8.1 and later).
400 =item use encoding I<ENCNAME> Filter=E<gt>1;
402 This turns the encoding pragma into a source filter. While the
403 default approach just decodes interpolated literals (in qq() and
404 qr()), this will apply a source filter to the entire source code. See
405 L</"The Filter Option"> below for details.
409 Unsets the script encoding. The layers of STDIN, STDOUT are
410 reset to ":raw" (the default unprocessed raw stream of bytes).
414 =head1 The Filter Option
416 The magic of C<use encoding> is not applied to the names of
417 identifiers. In order to make C<${"\x{4eba}"}++> ($human++, where human
418 is a single Han ideograph) work, you still need to write your script
419 in UTF-8 -- or use a source filter. That's what 'Filter=>1' does.
421 What does this mean? Your source code behaves as if it is written in
422 UTF-8 with 'use utf8' in effect. So even if your editor only supports
423 Shift_JIS, for example, you can still try examples in Chapter 15 of
424 C<Programming Perl, 3rd Ed.>. For instance, you can use UTF-8
427 This option is significantly slower and (as of this writing) non-ASCII
428 identifiers are not very stable WITHOUT this option and with the
429 source code written in UTF-8.
431 =head2 Filter-related changes at Encode version 1.87
437 The Filter option now sets STDIN and STDOUT like non-filter options.
438 And C<< STDIN=>I<ENCODING> >> and C<< STDOUT=>I<ENCODING> >> work like
443 C<use utf8> is implicitly declared so you no longer have to C<use
444 utf8> to C<${"\x{4eba}"}++>.
452 The pragma is a per script, not a per block lexical. Only the last
453 C<use encoding> or C<no encoding> matters, and it affects
454 B<the whole script>. However, the <no encoding> pragma is supported and
455 B<use encoding> can appear as many times as you want in a given script.
456 The multiple use of this pragma is discouraged.
458 By the same reason, the use this pragma inside modules is also
459 discouraged (though not as strongly discouraged as the case above.
462 If you still have to write a module with this pragma, be very careful
463 of the load order. See the codes below;
466 package Module_IN_BAR;
468 # stuff in "bar" encoding here
474 # surprise! use encoding "bar" is in effect.
476 The best way to avoid this oddity is to use this pragma RIGHT AFTER
477 other modules are loaded. i.e.
482 =head2 DO NOT MIX MULTIPLE ENCODINGS
484 Notice that only literals (string or regular expression) having only
485 legacy code points are affected: if you mix data like this
489 the data is assumed to be in (Latin 1 and) Unicode, not in your native
490 encoding. In other words, this will match in "greek":
496 "\xDF\x{100}" =~ /\x{3af}\x{100}/
498 since the C<\xDF> (ISO 8859-7 GREEK SMALL LETTER IOTA WITH TONOS) on
499 the left will B<not> be upgraded to C<\x{3af}> (Unicode GREEK SMALL
500 LETTER IOTA WITH TONOS) because of the C<\x{100}> on the left. You
501 should not be mixing your legacy data and Unicode in the same string.
503 This pragma also affects encoding of the 0x80..0xFF code point range:
504 normally characters in that range are left as eight-bit bytes (unless
505 they are combined with characters with code points 0x100 or larger,
506 in which case all characters need to become UTF-8 encoded), but if
507 the C<encoding> pragma is present, even the 0x80..0xFF range always
510 After all, the best thing about this pragma is that you don't have to
511 resort to \x{....} just to spell your name in a native encoding.
512 So feel free to put your strings in your encoding in quotes and
515 =head2 tr/// with ranges
517 The B<encoding> pragma works by decoding string literals in
518 C<q//,qq//,qr//,qw///, qx//> and so forth. In perl 5.8.0, this
519 does not apply to C<tr///>. Therefore,
521 use encoding 'euc-jp';
523 $kana =~ tr/\xA4\xA1-\xA4\xF3/\xA5\xA1-\xA5\xF3/;
524 # -------- -------- -------- --------
528 $kana =~ tr/\x{3041}-\x{3093}/\x{30a1}-\x{30f3}/;
532 =item Legend of characters above
534 utf8 euc-jp charnames::viacode()
535 -----------------------------------------
536 \x{3041} \xA4\xA1 HIRAGANA LETTER SMALL A
537 \x{3093} \xA4\xF3 HIRAGANA LETTER N
538 \x{30a1} \xA5\xA1 KATAKANA LETTER SMALL A
539 \x{30f3} \xA5\xF3 KATAKANA LETTER N
543 This counterintuitive behavior has been fixed in perl 5.8.1.
545 =head3 workaround to tr///;
547 In perl 5.8.0, you can work around as follows;
549 use encoding 'euc-jp';
551 eval qq{ \$kana =~ tr/\xA4\xA1-\xA4\xF3/\xA5\xA1-\xA5\xF3/ };
553 Note the C<tr//> expression is surrounded by C<qq{}>. The idea behind
554 is the same as classic idiom that makes C<tr///> 'interpolate'.
556 tr/$from/$to/; # wrong!
557 eval qq{ tr/$from/$to/ }; # workaround.
559 Nevertheless, in case of B<encoding> pragma even C<q//> is affected so
560 C<tr///> not being decoded was obviously against the will of Perl5
561 Porters so it has been fixed in Perl 5.8.1 or later.
563 =head1 EXAMPLE - Greekperl
565 use encoding "iso 8859-7";
567 # \xDF in ISO 8859-7 (Greek) is \x{3af} in Unicode.
572 printf "%#x\n", ord($a); # will print 0x3af, not 0xdf
576 # $c will be "\x{3af}\x{100}", not "\x{df}\x{100}".
578 # chr() is affected, and ...
580 print "mega\n" if ord(chr(0xdf)) == 0x3af;
582 # ... ord() is affected by the encoding pragma ...
584 print "tera\n" if ord(pack("C", 0xdf)) == 0x3af;
586 # ... as are eq and cmp ...
588 print "peta\n" if "\x{3af}" eq pack("C", 0xdf);
589 print "exa\n" if "\x{3af}" cmp pack("C", 0xdf) == 0;
591 # ... but pack/unpack C are not affected, in case you still
592 # want to go back to your native encoding
594 print "zetta\n" if unpack("C", (pack("C", 0xdf))) == 0xdf;
596 =head1 KNOWN PROBLEMS
600 =item literals in regex that are longer than 127 bytes
602 For native multibyte encodings (either fixed or variable length),
603 the current implementation of the regular expressions may introduce
604 recoding errors for regular expression literals longer than 127 bytes.
608 The encoding pragma is not supported on EBCDIC platforms.
609 (Porters who are willing and able to remove this limitation are
614 This pragma doesn't work well with format because PerlIO does not
615 get along very well with it. When format contains non-ascii
616 characters it prints funny or gets "wide character warnings".
617 To understand it, try the code below.
619 # Save this one in utf8
620 # replace *non-ascii* with a non-ascii string
626 $camel = "*non-ascii*";
627 binmode(STDOUT=>':encoding(utf8)'); # bang!
629 print $camel, "\n"; # fine
631 Without binmode this happens to work but without binmode, print()
632 fails instead of write().
634 At any rate, the very use of format is questionable when it comes to
635 unicode characters since you have to consider such things as character
636 width (i.e. double-width for ideographs) and directions (i.e. BIDI for
641 C<use encoding ...> is not thread-safe (i.e., do not use in threaded
646 =head2 The Logic of :locale
648 The logic of C<:locale> is as follows:
654 If the platform supports the langinfo(CODESET) interface, the codeset
655 returned is used as the default encoding for the open pragma.
659 If 1. didn't work but we are under the locale pragma, the environment
660 variables LC_ALL and LANG (in that order) are matched for encodings
661 (the part after C<.>, if any), and if any found, that is used
662 as the default encoding for the open pragma.
666 If 1. and 2. didn't work, the environment variables LC_ALL and LANG
667 (in that order) are matched for anything looking like UTF-8, and if
668 any found, C<:utf8> is used as the default encoding for the open
673 If your locale environment variables (LC_ALL, LC_CTYPE, LANG)
674 contain the strings 'UTF-8' or 'UTF8' (case-insensitive matching),
675 the default encoding of your STDIN, STDOUT, and STDERR, and of
676 B<any subsequent file open>, is UTF-8.
680 This pragma first appeared in Perl 5.8.0. For features that require
681 5.8.1 and better, see above.
683 The C<:locale> subpragma was implemented in 2.01, or Perl 5.8.6.
687 L<perlunicode>, L<Encode>, L<open>, L<Filter::Util::Call>,
689 Ch. 15 of C<Programming Perl (3rd Edition)>
690 by Larry Wall, Tom Christiansen, Jon Orwant;
691 O'Reilly & Associates; ISBN 0-596-00027-8