Commit | Line | Data |
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a0ed51b3 LW |
1 | package utf8; |
2 | ||
d5448623 GS |
3 | $utf8::hint_bits = 0x00800000; |
4 | ||
20a6717b | 5 | our $VERSION = '1.03'; |
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 | ||
2c9359a2 | 34 | # Convert a Perl scalar to/from UTF-8. |
973655a8 SB |
35 | $num_octets = utf8::upgrade($string); |
36 | $success = utf8::downgrade($string[, FAIL_OK]); | |
37 | ||
2c9359a2 | 38 | # Change the native bytes of a Perl scalar to/from UTF-8 bytes. |
973655a8 SB |
39 | utf8::encode($string); |
40 | utf8::decode($string); | |
41 | ||
786c9463 | 42 | $flag = utf8::is_utf8(STRING); # since Perl 5.8.1 |
973655a8 SB |
43 | $flag = utf8::valid(STRING); |
44 | ||
a0ed51b3 LW |
45 | =head1 DESCRIPTION |
46 | ||
393fec97 | 47 | The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the |
b3419ed8 | 48 | program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based |
70122e76 | 49 | platforms). The C<no utf8> pragma tells Perl to switch back to treating |
b3419ed8 | 50 | the source text as literal bytes in the current lexical scope. |
a0ed51b3 | 51 | |
393fec97 GS |
52 | This pragma is primarily a compatibility device. Perl versions |
53 | earlier than 5.6 allowed arbitrary bytes in source code, whereas | |
54 | in future we would like to standardize on the UTF-8 encoding for | |
63708e74 JH |
55 | source text. |
56 | ||
19b49582 JH |
57 | B<Do not use this pragma for anything else than telling Perl that your |
58 | script is written in UTF-8.> The utility functions described below are | |
59 | useful for their own purposes, but they are not really part of the | |
60 | "pragmatic" effect. | |
61 | ||
63708e74 JH |
62 | Until UTF-8 becomes the default format for source text, either this |
63 | pragma or the L</encoding> pragma should be used to recognize UTF-8 | |
64 | in the source. When UTF-8 becomes the standard source format, this | |
65 | pragma will effectively become a no-op. For convenience in what | |
66 | follows the term I<UTF-X> is used to refer to UTF-8 on ASCII and ISO | |
67 | Latin based platforms and UTF-EBCDIC on EBCDIC based platforms. | |
a0ed51b3 | 68 | |
a74e8b45 JH |
69 | See also the effects of the C<-C> switch and its cousin, the |
70 | C<$ENV{PERL_UNICODE}>, in L<perlrun>. | |
71 | ||
ad0029c4 | 72 | Enabling the C<utf8> pragma has the following effect: |
a0ed51b3 | 73 | |
4ac9195f | 74 | =over 4 |
a0ed51b3 LW |
75 | |
76 | =item * | |
77 | ||
393fec97 | 78 | Bytes in the source text that have their high-bit set will be treated |
ad0029c4 | 79 | as being part of a literal UTF-8 character. This includes most |
c20e2abd | 80 | literals such as identifier names, string constants, and constant |
8f8cf39c JH |
81 | regular expression patterns. |
82 | ||
83 | On EBCDIC platforms characters in the Latin 1 character set are | |
84 | treated as being part of a literal UTF-EBCDIC character. | |
a0ed51b3 | 85 | |
4ac9195f MS |
86 | =back |
87 | ||
ae90e350 JH |
88 | Note that if you have bytes with the eighth bit on in your script |
89 | (for example embedded Latin-1 in your string literals), C<use utf8> | |
90 | will be unhappy since the bytes are most probably not well-formed | |
91 | UTF-8. If you want to have such bytes and use utf8, you can disable | |
92 | utf8 until the end the block (or file, if at top level) by C<no utf8;>. | |
93 | ||
63708e74 JH |
94 | If you want to automatically upgrade your 8-bit legacy bytes to UTF-8, |
95 | use the L</encoding> pragma instead of this pragma. For example, if | |
96 | you want to implicitly upgrade your ISO 8859-1 (Latin-1) bytes to UTF-8 | |
97 | as used in e.g. C<chr()> and C<\x{...}>, try this: | |
98 | ||
99 | use encoding "latin-1"; | |
100 | my $c = chr(0xc4); | |
101 | my $x = "\x{c5}"; | |
102 | ||
103 | In case you are wondering: yes, C<use encoding 'utf8';> works much | |
104 | the same as C<use utf8;>. | |
105 | ||
1b026014 NIS |
106 | =head2 Utility functions |
107 | ||
8800c35a JH |
108 | The following functions are defined in the C<utf8::> package by the |
109 | Perl core. You do not need to say C<use utf8> to use these and in fact | |
19b49582 | 110 | you should not say that unless you really want to have UTF-8 source code. |
1b026014 NIS |
111 | |
112 | =over 4 | |
113 | ||
973655a8 | 114 | =item * $num_octets = utf8::upgrade($string) |
1b026014 | 115 | |
6e37fd2a JH |
116 | Converts (in-place) internal representation of string to Perl's |
117 | internal I<UTF-X> form. Returns the number of octets necessary to | |
118 | represent the string as I<UTF-X>. Can be used to make sure that the | |
8dd9dd9f | 119 | UTF-8 flag is on, so that C<\w> or C<lc()> work as expected on strings |
6e37fd2a JH |
120 | containing characters in the range 0x80-0xFF (oon ASCII and |
121 | derivatives). Note that this should not be used to convert a legacy | |
122 | byte encoding to Unicode: use Encode for that. Affected by the | |
123 | encoding pragma. | |
1b026014 | 124 | |
973655a8 | 125 | =item * $success = utf8::downgrade($string[, FAIL_OK]) |
1b026014 | 126 | |
7d865a91 JH |
127 | Converts (in-place) internal representation of string to be un-encoded |
128 | bytes. Returns true on success. On failure dies or, if the value of | |
129 | FAIL_OK is true, returns false. Can be used to make sure that the | |
8dd9dd9f A |
130 | UTF-8 flag is off, e.g. when you want to make sure that the substr() |
131 | or length() function works with the usually faster byte algorithm. | |
13a6c0e0 JH |
132 | Note that this should not be used to convert Unicode back to a legacy |
133 | byte encoding: use Encode for that. B<Not> affected by the encoding | |
134 | pragma. | |
1b026014 NIS |
135 | |
136 | =item * utf8::encode($string) | |
137 | ||
2c9359a2 RGS |
138 | Converts in-place the octets of the I<$string> to the octet sequence |
139 | in Perl's I<UTF-X> encoding. Returns nothing. B<Note that this does | |
140 | not change the "type" of I<$string> to UTF-8>, and that this handles | |
141 | only ISO 8859-1 (or EBCDIC) as the source character set. Therefore | |
142 | this should not be used to convert a legacy 8-bit encoding to Unicode: | |
143 | use Encode::decode() for that. In the very limited case of wanting to | |
144 | handle just ISO 8859-1 (or EBCDIC), you could use utf8::upgrade(). | |
094ce63c | 145 | |
973655a8 | 146 | =item * utf8::decode($string) |
1b026014 | 147 | |
ad0029c4 | 148 | Attempts to convert I<$string> in-place from Perl's I<UTF-X> encoding |
2c9359a2 RGS |
149 | into octets. Returns nothing. B<Note that this does not change the |
150 | "type" of <$string> from UTF-8>, and that this handles only ISO 8859-1 | |
151 | (or EBCDIC) as the destination character set. Therefore this should | |
152 | not be used to convert Unicode back to a legacy 8-bit encoding: | |
153 | use Encode::encode() for that. In the very limited case of wanting | |
154 | to handle just ISO 8859-1 (or EBCDIC), you could use utf8::downgrade(). | |
1b026014 | 155 | |
8800c35a JH |
156 | =item * $flag = utf8::is_utf8(STRING) |
157 | ||
786c9463 JH |
158 | (Since Perl 5.8.1) Test whether STRING is in UTF-8. Functionally |
159 | the same as Encode::is_utf8(). | |
8800c35a | 160 | |
70122e76 JH |
161 | =item * $flag = utf8::valid(STRING) |
162 | ||
8800c35a JH |
163 | [INTERNAL] Test whether STRING is in a consistent state regarding |
164 | UTF-8. Will return true is well-formed UTF-8 and has the UTF-8 flag | |
165 | on B<or> if string is held as bytes (both these states are 'consistent'). | |
166 | Main reason for this routine is to allow Perl's testsuite to check | |
167 | that operations have left strings in a consistent state. You most | |
168 | probably want to use utf8::is_utf8() instead. | |
70122e76 | 169 | |
1b026014 NIS |
170 | =back |
171 | ||
7d865a91 JH |
172 | C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is |
173 | cleared. See L<perlunicode> for more on the UTF8 flag and the C API | |
174 | functions C<sv_utf8_upgrade>, C<sv_utf8_downgrade>, C<sv_utf8_encode>, | |
094ce63c AT |
175 | and C<sv_utf8_decode>, which are wrapped by the Perl functions |
176 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and | |
786c9463 JH |
177 | C<utf8::decode>. Note that in the Perl 5.8.0 and 5.8.1 implementation |
178 | the functions utf8::is_utf8, utf8::valid, utf8::encode, utf8::decode, | |
6e37fd2a JH |
179 | utf8::upgrade, and utf8::downgrade are always available, without a |
180 | C<require utf8> statement-- this may change in future releases. | |
f1e62f77 | 181 | |
8f8cf39c JH |
182 | =head1 BUGS |
183 | ||
184 | One can have Unicode in identifier names, but not in package/class or | |
185 | subroutine names. While some limited functionality towards this does | |
186 | exist as of Perl 5.8.0, that is more accidental than designed; use of | |
187 | Unicode for the said purposes is unsupported. | |
188 | ||
189 | One reason of this unfinishedness is its (currently) inherent | |
190 | unportability: since both package names and subroutine names may need | |
191 | to be mapped to file and directory names, the Unicode capability of | |
192 | the filesystem becomes important-- and there unfortunately aren't | |
193 | portable answers. | |
194 | ||
393fec97 | 195 | =head1 SEE ALSO |
a0ed51b3 | 196 | |
a74e8b45 | 197 | L<perluniintro>, L<encoding>, L<perlrun>, L<bytes>, L<perlunicode> |
a0ed51b3 LW |
198 | |
199 | =cut |