Commit | Line | Data |
---|---|---|
a0ed51b3 LW |
1 | package utf8; |
2 | ||
d5448623 GS |
3 | $utf8::hint_bits = 0x00800000; |
4 | ||
b75c8c73 MS |
5 | our $VERSION = '1.00'; |
6 | ||
a0ed51b3 | 7 | sub import { |
d5448623 | 8 | $^H |= $utf8::hint_bits; |
a0ed51b3 LW |
9 | $enc{caller()} = $_[1] if $_[1]; |
10 | } | |
11 | ||
12 | sub unimport { | |
d5448623 | 13 | $^H &= ~$utf8::hint_bits; |
a0ed51b3 LW |
14 | } |
15 | ||
16 | sub AUTOLOAD { | |
17 | require "utf8_heavy.pl"; | |
daf4d4ea SC |
18 | goto &$AUTOLOAD if defined &$AUTOLOAD; |
19 | Carp::croak("Undefined subroutine $AUTOLOAD called"); | |
a0ed51b3 LW |
20 | } |
21 | ||
22 | 1; | |
23 | __END__ | |
24 | ||
25 | =head1 NAME | |
26 | ||
b3419ed8 | 27 | utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code |
a0ed51b3 LW |
28 | |
29 | =head1 SYNOPSIS | |
30 | ||
31 | use utf8; | |
32 | no utf8; | |
33 | ||
34 | =head1 DESCRIPTION | |
35 | ||
393fec97 | 36 | The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the |
b3419ed8 | 37 | program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based |
70122e76 | 38 | platforms). The C<no utf8> pragma tells Perl to switch back to treating |
b3419ed8 | 39 | the source text as literal bytes in the current lexical scope. |
a0ed51b3 | 40 | |
393fec97 GS |
41 | This pragma is primarily a compatibility device. Perl versions |
42 | earlier than 5.6 allowed arbitrary bytes in source code, whereas | |
43 | in future we would like to standardize on the UTF-8 encoding for | |
44 | source text. Until UTF-8 becomes the default format for source | |
45 | text, this pragma should be used to recognize UTF-8 in the source. | |
46 | When UTF-8 becomes the standard source format, this pragma will | |
b3419ed8 | 47 | effectively become a no-op. For convenience in what follows the |
ad0029c4 | 48 | term I<UTF-X> is used to refer to UTF-8 on ASCII and ISO Latin based |
b3419ed8 | 49 | platforms and UTF-EBCDIC on EBCDIC based platforms. |
a0ed51b3 | 50 | |
ad0029c4 | 51 | Enabling the C<utf8> pragma has the following effect: |
a0ed51b3 | 52 | |
4ac9195f | 53 | =over 4 |
a0ed51b3 LW |
54 | |
55 | =item * | |
56 | ||
393fec97 | 57 | Bytes in the source text that have their high-bit set will be treated |
ad0029c4 | 58 | as being part of a literal UTF-8 character. This includes most |
c20e2abd JH |
59 | literals such as identifier names, string constants, and constant |
60 | regular expression patterns. On EBCDIC platforms characters in | |
61 | the Latin 1 character set are treated as being part of a literal | |
ad0029c4 | 62 | UTF-EBCDIC character. |
a0ed51b3 | 63 | |
4ac9195f MS |
64 | =back |
65 | ||
ae90e350 JH |
66 | Note that if you have bytes with the eighth bit on in your script |
67 | (for example embedded Latin-1 in your string literals), C<use utf8> | |
68 | will be unhappy since the bytes are most probably not well-formed | |
69 | UTF-8. If you want to have such bytes and use utf8, you can disable | |
70 | utf8 until the end the block (or file, if at top level) by C<no utf8;>. | |
71 | ||
1b026014 NIS |
72 | =head2 Utility functions |
73 | ||
74 | The following functions are defined in the C<utf8::> package by the perl core. | |
75 | ||
76 | =over 4 | |
77 | ||
78 | =item * $num_octets = utf8::upgrade($string); | |
79 | ||
8dd9dd9f | 80 | Converts (in-place) internal representation of string to Perl's internal |
ad0029c4 | 81 | I<UTF-X> form. Returns the number of octets necessary to represent |
8dd9dd9f A |
82 | the string as I<UTF-X>. Can be used to make sure that the |
83 | UTF-8 flag is on, so that C<\w> or C<lc()> work as expected on strings | |
84 | containing characters in the range 0x80-0xFF. Note that this should | |
85 | not be used to convert | |
13a6c0e0 JH |
86 | a legacy byte encoding to Unicode: use Encode for that. Affected |
87 | by the encoding pragma. | |
1b026014 | 88 | |
8dd9dd9f | 89 | =item * utf8::downgrade($string[, FAIL_OK]) |
1b026014 | 90 | |
7d865a91 JH |
91 | Converts (in-place) internal representation of string to be un-encoded |
92 | bytes. Returns true on success. On failure dies or, if the value of | |
93 | FAIL_OK is true, returns false. Can be used to make sure that the | |
8dd9dd9f A |
94 | UTF-8 flag is off, e.g. when you want to make sure that the substr() |
95 | or length() function works with the usually faster byte algorithm. | |
13a6c0e0 JH |
96 | Note that this should not be used to convert Unicode back to a legacy |
97 | byte encoding: use Encode for that. B<Not> affected by the encoding | |
98 | pragma. | |
1b026014 NIS |
99 | |
100 | =item * utf8::encode($string) | |
101 | ||
13a6c0e0 | 102 | Converts (in-place) I<$string> from logical characters to octet |
8dd9dd9f | 103 | sequence representing it in Perl's I<UTF-X> encoding. Same as |
7d865a91 JH |
104 | Encode::encode_utf8(). Note that this should not be used to convert |
105 | a legacy byte encoding to Unicode: use Encode for that. | |
094ce63c AT |
106 | |
107 | =item * $flag = utf8::decode($string) | |
1b026014 | 108 | |
ad0029c4 | 109 | Attempts to convert I<$string> in-place from Perl's I<UTF-X> encoding |
7d865a91 JH |
110 | into logical characters. Same as Encode::decode_utf8(). Note that this |
111 | should not be used to convert Unicode back to a legacy byte encoding: | |
112 | use Encode for that. | |
1b026014 | 113 | |
70122e76 JH |
114 | =item * $flag = utf8::valid(STRING) |
115 | ||
116 | [INTERNAL] Test whether STRING is in a consistent state. Will return | |
117 | true if string is held as bytes, or is well-formed UTF-8 and has the | |
118 | UTF-8 flag on. Main reason for this routine is to allow Perl's | |
119 | testsuite to check that operations have left strings in a consistent | |
120 | state. | |
121 | ||
1b026014 NIS |
122 | =back |
123 | ||
7d865a91 JH |
124 | C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is |
125 | cleared. See L<perlunicode> for more on the UTF8 flag and the C API | |
126 | functions C<sv_utf8_upgrade>, C<sv_utf8_downgrade>, C<sv_utf8_encode>, | |
094ce63c AT |
127 | and C<sv_utf8_decode>, which are wrapped by the Perl functions |
128 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and | |
7d865a91 JH |
129 | C<utf8::decode>. Note that in the Perl 5.8.0 implementation the |
130 | functions utf8::valid, utf8::encode, utf8::decode, utf8::upgrade, | |
131 | and utf8::downgrade are always available, without a C<require utf8> | |
132 | statement-- this may change in future releases. | |
f1e62f77 | 133 | |
393fec97 | 134 | =head1 SEE ALSO |
a0ed51b3 | 135 | |
8058d7ab | 136 | L<perlunicode>, L<bytes> |
a0ed51b3 LW |
137 | |
138 | =cut |