Commit | Line | Data |
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a0ed51b3 LW |
1 | package utf8; |
2 | ||
d5448623 GS |
3 | $utf8::hint_bits = 0x00800000; |
4 | ||
836ccc8e | 5 | our $VERSION = '1.08'; |
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 | 18 | goto &$AUTOLOAD if defined &$AUTOLOAD; |
bd7017d3 | 19 | require Carp; |
daf4d4ea | 20 | Carp::croak("Undefined subroutine $AUTOLOAD called"); |
a0ed51b3 LW |
21 | } |
22 | ||
23 | 1; | |
24 | __END__ | |
25 | ||
26 | =head1 NAME | |
27 | ||
b3419ed8 | 28 | utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code |
a0ed51b3 LW |
29 | |
30 | =head1 SYNOPSIS | |
31 | ||
32 | use utf8; | |
33 | no utf8; | |
34 | ||
836ccc8e DM |
35 | # Convert the internal representation of a Perl scalar to/from UTF-8. |
36 | ||
973655a8 SB |
37 | $num_octets = utf8::upgrade($string); |
38 | $success = utf8::downgrade($string[, FAIL_OK]); | |
39 | ||
836ccc8e DM |
40 | # Change each character of a Perl scalar to/from a series of |
41 | # characters that represent the UTF-8 bytes of each original character. | |
42 | ||
43 | utf8::encode($string); # "\x{100}" becomes "\xc4\x80" | |
44 | utf8::decode($string); # "\xc4\x80" becomes "\x{100}" | |
973655a8 | 45 | |
786c9463 | 46 | $flag = utf8::is_utf8(STRING); # since Perl 5.8.1 |
973655a8 SB |
47 | $flag = utf8::valid(STRING); |
48 | ||
a0ed51b3 LW |
49 | =head1 DESCRIPTION |
50 | ||
393fec97 | 51 | The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the |
b3419ed8 | 52 | program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based |
70122e76 | 53 | platforms). The C<no utf8> pragma tells Perl to switch back to treating |
b3419ed8 | 54 | the source text as literal bytes in the current lexical scope. |
a0ed51b3 | 55 | |
19b49582 JH |
56 | B<Do not use this pragma for anything else than telling Perl that your |
57 | script is written in UTF-8.> The utility functions described below are | |
2575c402 JW |
58 | directly usable without C<use utf8;>. |
59 | ||
60 | Because it is not possible to reliably tell UTF-8 from native 8 bit | |
61 | encodings, you need either a Byte Order Mark at the beginning of your | |
62 | source code, or C<use utf8;>, to instruct perl. | |
19b49582 | 63 | |
2575c402 JW |
64 | When UTF-8 becomes the standard source format, this pragma will |
65 | effectively become a no-op. For convenience in what follows the term | |
66 | I<UTF-X> is used to refer to UTF-8 on ASCII and ISO Latin based | |
67 | platforms and UTF-EBCDIC on EBCDIC based platforms. | |
a0ed51b3 | 68 | |
a74e8b45 JH |
69 | See also the effects of the C<-C> switch and its cousin, the |
70 | C<$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 |
2fa62f66 | 79 | as being part of a literal UTF-X sequence. 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 | |
2fa62f66 AT |
91 | UTF-X. If you want to have such bytes under C<use utf8>, you can disable |
92 | this pragma until the end the block (or file, if at top level) by | |
93 | C<no utf8;>. | |
ae90e350 | 94 | |
1b026014 NIS |
95 | =head2 Utility functions |
96 | ||
8800c35a JH |
97 | The following functions are defined in the C<utf8::> package by the |
98 | Perl core. You do not need to say C<use utf8> to use these and in fact | |
19b49582 | 99 | you should not say that unless you really want to have UTF-8 source code. |
1b026014 NIS |
100 | |
101 | =over 4 | |
102 | ||
973655a8 | 103 | =item * $num_octets = utf8::upgrade($string) |
1b026014 | 104 | |
836ccc8e DM |
105 | Converts in-place the internal representation of the string from an octet |
106 | sequence in the native encoding (Latin-1 or EBCDIC) to I<UTF-X>. The | |
107 | logical character sequence itself is unchanged. If I<$string> is already | |
108 | stored as I<UTF-X>, then this is a no-op. Returns the | |
2575c402 JW |
109 | number of octets necessary to represent the string as I<UTF-X>. Can be |
110 | used to make sure that the UTF-8 flag is on, so that C<\w> or C<lc()> | |
111 | work as Unicode on strings containing characters in the range 0x80-0xFF | |
112 | (on ASCII and derivatives). | |
78ea37eb TS |
113 | |
114 | B<Note that this function does not handle arbitrary encodings.> | |
2575c402 JW |
115 | Therefore Encode is recommended for the general purposes; see also |
116 | L<Encode>. | |
1b026014 | 117 | |
973655a8 | 118 | =item * $success = utf8::downgrade($string[, FAIL_OK]) |
1b026014 | 119 | |
836ccc8e DM |
120 | Converts in-place the the internal representation of the string from |
121 | I<UTF-X> to the equivalent octet sequence in the native encoding (Latin-1 | |
122 | or EBCDIC). The logical character sequence itself is unchanged. If | |
123 | I<$string> is already stored as native 8 bit, then this is a no-op. Can | |
124 | be used to | |
2575c402 JW |
125 | make sure that the UTF-8 flag is off, e.g. when you want to make sure |
126 | that the substr() or length() function works with the usually faster | |
127 | byte algorithm. | |
78ea37eb | 128 | |
2575c402 JW |
129 | Fails if the original I<UTF-X> sequence cannot be represented in the |
130 | native 8 bit encoding. On failure dies or, if the value of C<FAIL_OK> is | |
131 | true, returns false. | |
78ea37eb | 132 | |
2575c402 JW |
133 | Returns true on success. |
134 | ||
135 | B<Note that this function does not handle arbitrary encodings.> | |
136 | Therefore Encode is recommended for the general purposes; see also | |
137 | L<Encode>. | |
78ea37eb | 138 | |
1b026014 NIS |
139 | =item * utf8::encode($string) |
140 | ||
2575c402 | 141 | Converts in-place the character sequence to the corresponding octet |
836ccc8e DM |
142 | sequence in I<UTF-X>. That is, every (possibly wide) character gets |
143 | replaced with a sequence of one or more characters that represent the | |
144 | individual I<UTF-X> bytes of the character. The UTF8 flag is turned off. | |
145 | Returns nothing. | |
146 | ||
147 | my $a = "\x{100}"; # $a contains one character, with ord 0x100 | |
148 | utf8::encode($a); # $a contains two characters, with ords 0xc4 and 0x80 | |
78ea37eb TS |
149 | |
150 | B<Note that this function does not handle arbitrary encodings.> | |
2575c402 JW |
151 | Therefore Encode is recommended for the general purposes; see also |
152 | L<Encode>. | |
094ce63c | 153 | |
2575c402 | 154 | =item * $success = utf8::decode($string) |
1b026014 | 155 | |
2575c402 | 156 | Attempts to convert in-place the octet sequence in I<UTF-X> to the |
836ccc8e DM |
157 | corresponding character sequence. That is, it replaces each sequence of |
158 | characters in the string whose ords represent a valid UTF-X byte | |
159 | sequence, with the corresponding single character. The UTF-8 flag is | |
160 | turned on only if the source string contains multiple-byte I<UTF-X> | |
161 | characters. If I<$string> is invalid as I<UTF-X>, returns false; | |
162 | otherwise returns true. | |
163 | ||
164 | my $a = "\xc4\x80"; # $a contains two characters, with ords 0xc4 and 0x80 | |
165 | utf8::decode($a); # $a contains one character, with ord 0x100 | |
78ea37eb TS |
166 | |
167 | B<Note that this function does not handle arbitrary encodings.> | |
2575c402 JW |
168 | Therefore Encode is recommended for the general purposes; see also |
169 | L<Encode>. | |
78ea37eb | 170 | |
8800c35a JH |
171 | =item * $flag = utf8::is_utf8(STRING) |
172 | ||
2575c402 JW |
173 | (Since Perl 5.8.1) Test whether STRING is in UTF-8 internally. |
174 | Functionally the same as Encode::is_utf8(). | |
8800c35a | 175 | |
70122e76 JH |
176 | =item * $flag = utf8::valid(STRING) |
177 | ||
8800c35a JH |
178 | [INTERNAL] Test whether STRING is in a consistent state regarding |
179 | UTF-8. Will return true is well-formed UTF-8 and has the UTF-8 flag | |
180 | on B<or> if string is held as bytes (both these states are 'consistent'). | |
181 | Main reason for this routine is to allow Perl's testsuite to check | |
182 | that operations have left strings in a consistent state. You most | |
183 | probably want to use utf8::is_utf8() instead. | |
70122e76 | 184 | |
1b026014 NIS |
185 | =back |
186 | ||
7d865a91 JH |
187 | C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is |
188 | cleared. See L<perlunicode> for more on the UTF8 flag and the C API | |
189 | functions C<sv_utf8_upgrade>, C<sv_utf8_downgrade>, C<sv_utf8_encode>, | |
094ce63c AT |
190 | and C<sv_utf8_decode>, which are wrapped by the Perl functions |
191 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and | |
7edb8f2b RGS |
192 | C<utf8::decode>. Also, the functions utf8::is_utf8, utf8::valid, |
193 | utf8::encode, utf8::decode, utf8::upgrade, and utf8::downgrade are | |
194 | actually internal, and thus always available, without a C<require utf8> | |
195 | statement. | |
f1e62f77 | 196 | |
8f8cf39c JH |
197 | =head1 BUGS |
198 | ||
199 | One can have Unicode in identifier names, but not in package/class or | |
200 | subroutine names. While some limited functionality towards this does | |
201 | exist as of Perl 5.8.0, that is more accidental than designed; use of | |
202 | Unicode for the said purposes is unsupported. | |
203 | ||
204 | One reason of this unfinishedness is its (currently) inherent | |
205 | unportability: since both package names and subroutine names may need | |
206 | to be mapped to file and directory names, the Unicode capability of | |
207 | the filesystem becomes important-- and there unfortunately aren't | |
208 | portable answers. | |
209 | ||
393fec97 | 210 | =head1 SEE ALSO |
a0ed51b3 | 211 | |
2575c402 | 212 | L<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode> |
a0ed51b3 LW |
213 | |
214 | =cut |