Commit | Line | Data |
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a0ed51b3 LW |
1 | package utf8; |
2 | ||
d5448623 GS |
3 | $utf8::hint_bits = 0x00800000; |
4 | ||
2af1ab88 | 5 | our $VERSION = '1.01'; |
b75c8c73 | 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 | 59 | literals such as identifier names, string constants, and constant |
8f8cf39c JH |
60 | regular expression patterns. |
61 | ||
62 | On EBCDIC platforms characters in the Latin 1 character set are | |
63 | treated as being part of a literal UTF-EBCDIC character. | |
a0ed51b3 | 64 | |
4ac9195f MS |
65 | =back |
66 | ||
ae90e350 JH |
67 | Note that if you have bytes with the eighth bit on in your script |
68 | (for example embedded Latin-1 in your string literals), C<use utf8> | |
69 | will be unhappy since the bytes are most probably not well-formed | |
70 | UTF-8. If you want to have such bytes and use utf8, you can disable | |
71 | utf8 until the end the block (or file, if at top level) by C<no utf8;>. | |
72 | ||
1b026014 NIS |
73 | =head2 Utility functions |
74 | ||
8800c35a JH |
75 | The following functions are defined in the C<utf8::> package by the |
76 | Perl core. You do not need to say C<use utf8> to use these and in fact | |
77 | you should not unless you really want to have UTF-8 source code. | |
1b026014 NIS |
78 | |
79 | =over 4 | |
80 | ||
81 | =item * $num_octets = utf8::upgrade($string); | |
82 | ||
6e37fd2a JH |
83 | Converts (in-place) internal representation of string to Perl's |
84 | internal I<UTF-X> form. Returns the number of octets necessary to | |
85 | represent the string as I<UTF-X>. Can be used to make sure that the | |
8dd9dd9f | 86 | UTF-8 flag is on, so that C<\w> or C<lc()> work as expected on strings |
6e37fd2a JH |
87 | containing characters in the range 0x80-0xFF (oon ASCII and |
88 | derivatives). Note that this should not be used to convert a legacy | |
89 | byte encoding to Unicode: use Encode for that. Affected by the | |
90 | encoding pragma. | |
1b026014 | 91 | |
8dd9dd9f | 92 | =item * utf8::downgrade($string[, FAIL_OK]) |
1b026014 | 93 | |
7d865a91 JH |
94 | Converts (in-place) internal representation of string to be un-encoded |
95 | bytes. Returns true on success. On failure dies or, if the value of | |
96 | FAIL_OK is true, returns false. Can be used to make sure that the | |
8dd9dd9f A |
97 | UTF-8 flag is off, e.g. when you want to make sure that the substr() |
98 | or length() function works with the usually faster byte algorithm. | |
13a6c0e0 JH |
99 | Note that this should not be used to convert Unicode back to a legacy |
100 | byte encoding: use Encode for that. B<Not> affected by the encoding | |
101 | pragma. | |
1b026014 NIS |
102 | |
103 | =item * utf8::encode($string) | |
104 | ||
13a6c0e0 | 105 | Converts (in-place) I<$string> from logical characters to octet |
6e37fd2a JH |
106 | sequence representing it in Perl's I<UTF-X> encoding. Returns |
107 | nothing. Same as Encode::encode_utf8(). Note that this should not be | |
108 | used to convert a legacy byte encoding to Unicode: use Encode for | |
109 | that. | |
094ce63c AT |
110 | |
111 | =item * $flag = utf8::decode($string) | |
1b026014 | 112 | |
ad0029c4 | 113 | Attempts to convert I<$string> in-place from Perl's I<UTF-X> encoding |
6e37fd2a JH |
114 | into logical characters. Returns nothing. Same as Encode::decode_utf8(). |
115 | Note that this should not be used to convert Unicode back to a legacy | |
116 | byte encoding: use Encode for that. | |
1b026014 | 117 | |
8800c35a JH |
118 | =item * $flag = utf8::is_utf8(STRING) |
119 | ||
6e37fd2a | 120 | Test whether STRING is in UTF-8. Same as Encode::is_utf8(). |
8800c35a | 121 | |
70122e76 JH |
122 | =item * $flag = utf8::valid(STRING) |
123 | ||
8800c35a JH |
124 | [INTERNAL] Test whether STRING is in a consistent state regarding |
125 | UTF-8. Will return true is well-formed UTF-8 and has the UTF-8 flag | |
126 | on B<or> if string is held as bytes (both these states are 'consistent'). | |
127 | Main reason for this routine is to allow Perl's testsuite to check | |
128 | that operations have left strings in a consistent state. You most | |
129 | probably want to use utf8::is_utf8() instead. | |
70122e76 | 130 | |
1b026014 NIS |
131 | =back |
132 | ||
7d865a91 JH |
133 | C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is |
134 | cleared. See L<perlunicode> for more on the UTF8 flag and the C API | |
135 | functions C<sv_utf8_upgrade>, C<sv_utf8_downgrade>, C<sv_utf8_encode>, | |
094ce63c AT |
136 | and C<sv_utf8_decode>, which are wrapped by the Perl functions |
137 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and | |
7d865a91 | 138 | C<utf8::decode>. Note that in the Perl 5.8.0 implementation the |
6e37fd2a JH |
139 | functions utf8::is_utf8, utf8::valid, utf8::encode, utf8::decode, |
140 | utf8::upgrade, and utf8::downgrade are always available, without a | |
141 | C<require utf8> statement-- this may change in future releases. | |
f1e62f77 | 142 | |
8f8cf39c JH |
143 | =head1 BUGS |
144 | ||
145 | One can have Unicode in identifier names, but not in package/class or | |
146 | subroutine names. While some limited functionality towards this does | |
147 | exist as of Perl 5.8.0, that is more accidental than designed; use of | |
148 | Unicode for the said purposes is unsupported. | |
149 | ||
150 | One reason of this unfinishedness is its (currently) inherent | |
151 | unportability: since both package names and subroutine names may need | |
152 | to be mapped to file and directory names, the Unicode capability of | |
153 | the filesystem becomes important-- and there unfortunately aren't | |
154 | portable answers. | |
155 | ||
393fec97 | 156 | =head1 SEE ALSO |
a0ed51b3 | 157 | |
8058d7ab | 158 | L<perlunicode>, L<bytes> |
a0ed51b3 LW |
159 | |
160 | =cut |