2 our $VERSION = do { my @r = (q$Revision: 1.35 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r };
10 Carp::croak("encoding pragma does not support EBCDIC platforms");
15 eval { require PerlIO::encoding };
17 $HAS_PERLIO = (PerlIO::encoding->VERSION >= 0.02);
24 $name ||= $ENV{PERL_ENCODING};
26 my $enc = find_encoding($name);
27 unless (defined $enc) {
29 Carp::croak("Unknown encoding '$name'");
31 unless ($arg{Filter}){
32 ${^ENCODING} = $enc; # this is all you need, actually.
33 $HAS_PERLIO or return 1;
34 for my $h (qw(STDIN STDOUT)){
36 unless (defined find_encoding($arg{$h})) {
38 Carp::croak("Unknown encoding for $h, '$arg{$h}'");
40 eval { binmode($h, ":encoding($arg{$h})") };
42 unless (exists $arg{$h}){
44 no warnings 'uninitialized';
45 binmode($h, ":encoding($name)");
55 defined(${^ENCODING}) and undef ${^ENCODING};
57 require Filter::Util::Call ;
58 Filter::Util::Call->import ;
63 if (($status = filter_read()) > 0){
64 $_ = $enc->decode($_, 1);
70 # warn "Filter installed";
72 return 1; # I doubt if we need it, though
79 binmode(STDIN, ":raw");
80 binmode(STDOUT, ":raw");
85 if ($INC{"Filter/Util/Call.pm"}){
86 eval { filter_del() };
97 encoding - allows you to write your script in non-ascii or non-utf8
101 use encoding "greek"; # Perl like Greek to you?
102 use encoding "euc-jp"; # Jperl!
104 # or you can even do this if your shell supports your native encoding
106 perl -Mencoding=latin2 -e '...' # Feeling centrally European?
107 perl -Mencoding=euc-kr -e '...' # Or Korean?
109 # or from the shebang line
111 #!/your/path/to/perl -Mencoding="8859-6" # Arabian Nights
112 #!/your/path/to/perl -Mencoding=big5 # Taiwanese
116 # A simple euc-cn => utf-8 converter
117 use encoding "euc-cn", STDOUT => "utf8"; while(<>){print};
119 # "no encoding;" supported (but not scoped!)
122 # an alternate way, Filter
123 use encoding "euc-jp", Filter=>1;
125 # now you can use kanji identifiers -- in euc-jp!
129 Let's start with a bit of history: Perl 5.6.0 introduced Unicode
130 support. You could apply C<substr()> and regexes even to complex CJK
131 characters -- so long as the script was written in UTF-8. But back
132 then, text editors that supported UTF-8 were still rare and many users
133 instead chose to write scripts in legacy encodings, giving up a whole
134 new feature of Perl 5.6.
136 Rewind to the future: starting from perl 5.8.0 with the B<encoding>
137 pragma, you can write your script in any encoding you like (so long
138 as the C<Encode> module supports it) and still enjoy Unicode support.
139 You can write code in EUC-JP as follows:
141 my $Rakuda = "\xF1\xD1\xF1\xCC"; # Camel in Kanji
142 #<-char-><-char-> # 4 octets
143 s/\bCamel\b/$Rakuda/;
145 And with C<use encoding "euc-jp"> in effect, it is the same thing as
148 my $Rakuda = "\x{99F1}\x{99DD}"; # two Unicode Characters
149 s/\bCamel\b/$Rakuda/;
151 The B<encoding> pragma also modifies the filehandle disciplines of
152 STDIN, STDOUT, and STDERR to the specified encoding. Therefore,
154 use encoding "euc-jp";
155 my $message = "Camel is the symbol of perl.\n";
156 my $Rakuda = "\xF1\xD1\xF1\xCC"; # Camel in Kanji
157 $message =~ s/\bCamel\b/$Rakuda/;
160 Will print "\xF1\xD1\xF1\xCC is the symbol of perl.\n",
161 not "\x{99F1}\x{99DD} is the symbol of perl.\n".
163 You can override this by giving extra arguments; see below.
169 =item use encoding [I<ENCNAME>] ;
171 Sets the script encoding to I<ENCNAME>. Filehandle disciplines of
172 STDIN and STDOUT are set to ":encoding(I<ENCNAME>)". Note that STDERR
175 If no encoding is specified, the environment variable L<PERL_ENCODING>
176 is consulted. If no encoding can be found, the error C<Unknown encoding
177 'I<ENCNAME>'> will be thrown.
179 Note that non-STD file handles remain unaffected. Use C<use open> or
180 C<binmode> to change disciplines of those.
182 =item use encoding I<ENCNAME> [ STDIN =E<gt> I<ENCNAME_IN> ...] ;
184 You can also individually set encodings of STDIN and STDOUT via the
185 C<< STDIN => I<ENCNAME> >> form. In this case, you cannot omit the
186 first I<ENCNAME>. C<< STDIN => undef >> turns the IO transcoding
191 Unsets the script encoding. The disciplines of STDIN, STDOUT are
192 reset to ":raw" (the default unprocessed raw stream of bytes).
200 The pragma is a per script, not a per block lexical. Only the last
201 C<use encoding> or C<no encoding> matters, and it affects
202 B<the whole script>. However, the <no encoding> pragma is supported and
203 B<use encoding> can appear as many times as you want in a given script.
204 The multiple use of this pragma is discouraged.
206 Because of this nature, the use of this pragma inside the module is
207 strongly discouraged (because the influence of this pragma lasts not
208 only for the module but the script that uses). But if you have to,
209 make sure you say C<no encoding> at the end of the module so you
210 contain the influence of the pragma within the module.
212 =head2 DO NOT MIX MULTIPLE ENCODINGS
214 Notice that only literals (string or regular expression) having only
215 legacy code points are affected: if you mix data like this
219 the data is assumed to be in (Latin 1 and) Unicode, not in your native
220 encoding. In other words, this will match in "greek":
226 "\xDF\x{100}" =~ /\x{3af}\x{100}/
228 since the C<\xDF> (ISO 8859-7 GREEK SMALL LETTER IOTA WITH TONOS) on
229 the left will B<not> be upgraded to C<\x{3af}> (Unicode GREEK SMALL
230 LETTER IOTA WITH TONOS) because of the C<\x{100}> on the left. You
231 should not be mixing your legacy data and Unicode in the same string.
233 This pragma also affects encoding of the 0x80..0xFF code point range:
234 normally characters in that range are left as eight-bit bytes (unless
235 they are combined with characters with code points 0x100 or larger,
236 in which case all characters need to become UTF-8 encoded), but if
237 the C<encoding> pragma is present, even the 0x80..0xFF range always
240 After all, the best thing about this pragma is that you don't have to
241 resort to \x{....} just to spell your name in a native encoding.
242 So feel free to put your strings in your encoding in quotes and
245 =head1 Non-ASCII Identifiers and Filter option
247 The magic of C<use encoding> is not applied to the names of
248 identifiers. In order to make C<${"\x{4eba}"}++> ($human++, where human
249 is a single Han ideograph) work, you still need to write your script
250 in UTF-8 or use a source filter.
252 In other words, the same restriction as with Jperl applies.
254 If you dare to experiment, however, you can try the Filter option.
258 =item use encoding I<ENCNAME> Filter=E<gt>1;
260 This turns the encoding pragma into a source filter. While the default
261 approach just decodes interpolated literals (in qq() and qr()), this
262 will apply a source filter to the entire source code. In this case,
263 STDIN and STDOUT remain untouched.
267 What does this mean? Your source code behaves as if it is written in
268 UTF-8. So even if your editor only supports Shift_JIS, for example,
269 you can still try examples in Chapter 15 of C<Programming Perl, 3rd
270 Ed.>. For instance, you can use UTF-8 identifiers.
272 This option is significantly slower and (as of this writing) non-ASCII
273 identifiers are not very stable WITHOUT this option and with the
274 source code written in UTF-8.
276 To make your script in legacy encoding work with minimum effort,
277 do not use Filter=E<gt>1.
279 =head1 EXAMPLE - Greekperl
281 use encoding "iso 8859-7";
283 # \xDF in ISO 8859-7 (Greek) is \x{3af} in Unicode.
288 printf "%#x\n", ord($a); # will print 0x3af, not 0xdf
292 # $c will be "\x{3af}\x{100}", not "\x{df}\x{100}".
294 # chr() is affected, and ...
296 print "mega\n" if ord(chr(0xdf)) == 0x3af;
298 # ... ord() is affected by the encoding pragma ...
300 print "tera\n" if ord(pack("C", 0xdf)) == 0x3af;
302 # ... as are eq and cmp ...
304 print "peta\n" if "\x{3af}" eq pack("C", 0xdf);
305 print "exa\n" if "\x{3af}" cmp pack("C", 0xdf) == 0;
307 # ... but pack/unpack C are not affected, in case you still
308 # want to go back to your native encoding
310 print "zetta\n" if unpack("C", (pack("C", 0xdf))) == 0xdf;
312 =head1 KNOWN PROBLEMS
314 For native multibyte encodings (either fixed or variable length),
315 the current implementation of the regular expressions may introduce
316 recoding errors for regular expression literals longer than 127 bytes.
318 The encoding pragma is not supported on EBCDIC platforms.
319 (Porters who are willing and able to remove this limitation are
324 L<perlunicode>, L<Encode>, L<open>, L<Filter::Util::Call>,
326 Ch. 15 of C<Programming Perl (3rd Edition)>
327 by Larry Wall, Tom Christiansen, Jon Orwant;
328 O'Reilly & Associates; ISBN 0-596-00027-8