left-over "use 5.7.2" in threads.pm
[p5sagit/p5-mst-13.2.git] / ext / Encode / encoding.pm
CommitLineData
3ef515df 1package encoding;
2our $VERSION = do { my @r = (q$Revision: 1.2 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r };
3
4use Encode;
5
6BEGIN {
7 if (ord("A") == 193) {
8 require Carp;
9 Carp::croak "encoding pragma does not support EBCDIC platforms";
10 }
11}
12
13sub import {
14 my $class = shift;
15 my $name = shift;
16 my %arg = @_;
17 $name ||= $ENV{PERL_ENCODING};
18
19 my $enc = find_encoding($name);
20 unless (defined $enc) {
21 require Carp;
22 Carp::croak "Unknown encoding '$name'";
23 }
24 ${^ENCODING} = $enc; # this is all you need, actually.
25
26 # $_OPEN_ORIG = ${^OPEN};
27 for my $h (qw(STDIN STDOUT STDERR)){
28 if ($arg{$h}){
29 unless (defined find_encoding($name)) {
30 require Carp;
31 Carp::croak "Unknown encoding for $fhname, '$arg{$h}'";
32 }
33 eval qq{ binmode($h, ":encoding($arg{h})") };
34 }else{
35 eval qq{ binmode($h, ":encoding($name)") };
36 }
37 if ($@){
38 require Carp;
39 Carp::croak($@);
40 }
41 }
42 return 1; # I doubt if we need it, though
43}
44
45sub unimport{
46 no warnings;
47 undef ${^ENCODING};
48 binmode(STDIN, ":raw");
49 binmode(STDOUT, ":raw");
50 binmode(STDERR, ":raw");
51}
52
531;
54__END__
55=pod
56
57=head1 NAME
58
59encoding - allows you to write your script in non-asii or non-utf8
60
61=head1 SYNOPSIS
62
63 use encoding "euc-jp"; # Jperl!
64
65 # or you can even do this if your shell supports euc-jp
66
67 > perl -Mencoding=euc-jp -e '...'
68
69 # or from the shebang line
70
71 #!/your/path/to/perl -Mencoding=euc-jp
72
73 # more control
74
75 # A simple euc-jp => utf-8 converter
76 use encoding "euc-jp", STDOUT => "utf8"; while(<>){print};
77
78 # "no encoding;" supported (but not scoped!)
79 no encoding;
80
81=head1 ABSTRACT
82
83Perl 5.6.0 has introduced Unicode support. You could apply
84C<substr()> and regexes even to complex CJK characters -- so long as
85the script was written in UTF-8. But back then text editors that
86support UTF-8 was still rare and many users rather chose to writer
87scripts in legacy encodings, given up whole new feature of Perl 5.6.
88
89With B<encoding> pragma, you can write your script in any encoding you like
90(so long as the C<Encode> module supports it) and still enjoy Unicode
91support. You can write a code in EUC-JP as follows;
92
93 my $Rakuda = "\xF1\xD1\xF1\xCC"; # Camel in Kanji
94 #<-char-><-char-> # 4 octets
95 s/\bCamel\b/$Rakuda/;
96
97And with C<use encoding "euc-jp"> in effect, it is the same thing as
98the code in UTF-8 as follow.
99
100 my $Rakuda = "\x{99F1}\x{99DD}"; # who Unicode Characters
101 s/\bCamel\b/$Rakuda/;
102
103The B<encoding> pragma also modifies the file handle disciplines of
104STDIN, STDOUT, and STDERR to the specified encoding. Therefore,
105
106 use encoding "euc-jp";
107 my $message = "Camel is the symbol of perl.\n";
108 my $Rakuda = "\xF1\xD1\xF1\xCC"; # Camel in Kanji
109 $message =~ s/\bCamel\b/$Rakuda/;
110 print $message;
111
112Will print "\xF1\xD1\xF1\xCC is the symbol of perl.\n", not
113"\x{99F1}\x{99DD} is the symbol of perl.\n".
114
115You can override this by giving extra arguments. See below.
116
117=head1 USAGE
118
119=over 4
120
121=item use encoding [I<ENCNAME>] ;
122
123Sets the script encoding to I<ENCNAME> and file handle disciplines of
124STDIN, STDOUT, and STDERR are set to ":encoding(I<ENCNAME>)".
125
126If no encoding is specified, the environment variable L<PERL_ENCODING>
127is consulted. If no encoding can be found, C<Unknown encoding 'I<ENCNAME>'>
128error will be thrown.
129
130Note that non-STD file handles remain unaffected. Use C<use open> or
131C<binmode> to change disciplines of those.
132
133=item use encoding I<ENCNAME> [ STDIN => I<ENCNAME_IN> ...] ;
134
135You can also individually set encodings of STDIN, STDOUT, and STDERR
136via STDI<FH> => I<ENCNAME_FH> form. In this case, you cannot omit the
137first I<ENCNAME>.
138
139=item no encoding;
140
141Unsets the script encoding and the disciplines of STDIN, STDOUT, and
142STDERR are reset to ":raw".
143
144=back
145
146=head1 CAVEATS
147
148=head2 NOT SCOPED
149
150The pragma is a per script, not a per block lexical. Only the last
151C<use encoding> or C<matters, and it affects B<the whole script>.
152Though <no encoding> pragma is supported and C<use encoding> can
153appear as many times as you want in a given script, the multiple use
154of this pragma is discouraged.
155
156=head2 DO NOT MIX MULTIPLE ENCODINGS
157
158Notice that only literals (string or regular expression) having only
159legacy code points are affected: if you mix data like this
160
161 \xDF\x{100}
162
163the data is assumed to be in (Latin 1 and) Unicode, not in your native
164encoding. In other words, this will match in "greek":
165
166 "\xDF" =~ /\x{3af}/
167
168but this will not
169
170 "\xDF\x{100}" =~ /\x{3af}\x{100}/
171
172since the C<\xDF> on the left will B<not> be upgraded to C<\x{3af}>
173because of the C<\x{100}> on the left. You should not be mixing your
174legacy data and Unicode in the same string.
175
176This pragma also affects encoding of the 0x80..0xFF code point range:
177normally characters in that range are left as eight-bit bytes (unless
178they are combined with characters with code points 0x100 or larger,
179in which case all characters need to become UTF-8 encoded), but if
180the C<encoding> pragma is present, even the 0x80..0xFF range always
181gets UTF-8 encoded.
182
183After all, the best thing about this pragma is that you don't have to
184resort to \x... just to spell your name in native encoding. So feel
185free to put your strings in your encoding in quotes and regexes.
186
187=head1 EXAMPLE - Greekperl
188
189 use encoding "iso 8859-7";
190
191 # The \xDF of ISO 8859-7 (Greek) is \x{3af} in Unicode.
192
193 $a = "\xDF";
194 $b = "\x{100}";
195
196 printf "%#x\n", ord($a); # will print 0x3af, not 0xdf
197
198 $c = $a . $b;
199
200 # $c will be "\x{3af}\x{100}", not "\x{df}\x{100}".
201
202 # chr() is affected, and ...
203
204 print "mega\n" if ord(chr(0xdf)) == 0x3af;
205
206 # ... ord() is affected by the encoding pragma ...
207
208 print "tera\n" if ord(pack("C", 0xdf)) == 0x3af;
209
210 # ... as are eq and cmp ...
211
212 print "peta\n" if "\x{3af}" eq pack("C", 0xdf);
213 print "exa\n" if "\x{3af}" cmp pack("C", 0xdf) == 0;
214
215 # ... but pack/unpack C are not affected, in case you still
216 # want back to your native encoding
217
218 print "zetta\n" if unpack("C", (pack("C", 0xdf))) == 0xdf;
219
220=head1 KNOWN PROBLEMS
221
222For native multibyte encodings (either fixed or variable length)
223the current implementation of the regular expressions may introduce
224recoding errors for longer regular expression literals than 127 bytes.
225
226The encoding pragma is not supported on EBCDIC platforms.
227(Porters wanted.)
228
229=head1 SEE ALSO
230
231L<perlunicode>, L<Encode>, L<open>
232
233=cut