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a0ed51b3 LW |
1 | package utf8; |
2 | ||
d5448623 GS |
3 | $utf8::hint_bits = 0x00800000; |
4 | ||
ca3d51ba | 5 | our $VERSION = '1.14'; |
b75c8c73 | 6 | |
a0ed51b3 | 7 | sub import { |
d5448623 | 8 | $^H |= $utf8::hint_bits; |
a0ed51b3 LW |
9 | } |
10 | ||
11 | sub unimport { | |
d5448623 | 12 | $^H &= ~$utf8::hint_bits; |
a0ed51b3 LW |
13 | } |
14 | ||
15 | sub AUTOLOAD { | |
16 | require "utf8_heavy.pl"; | |
daf4d4ea | 17 | goto &$AUTOLOAD if defined &$AUTOLOAD; |
bd7017d3 | 18 | require Carp; |
daf4d4ea | 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 | ||
291cc134 KW |
31 | use utf8; |
32 | no utf8; | |
a0ed51b3 | 33 | |
291cc134 | 34 | # Convert the internal representation of a Perl scalar to/from UTF-8. |
836ccc8e | 35 | |
291cc134 | 36 | $num_octets = utf8::upgrade($string); |
98695e13 | 37 | $success = utf8::downgrade($string[, $fail_ok]); |
973655a8 | 38 | |
291cc134 KW |
39 | # Change each character of a Perl scalar to/from a series of |
40 | # characters that represent the UTF-8 bytes of each original character. | |
836ccc8e | 41 | |
291cc134 KW |
42 | utf8::encode($string); # "\x{100}" becomes "\xc4\x80" |
43 | utf8::decode($string); # "\xc4\x80" becomes "\x{100}" | |
973655a8 | 44 | |
ca3d51ba KW |
45 | # Convert a code point from the platform native character set to |
46 | # Unicode, and vice-versa. | |
47 | $unicode = utf8::native_to_unicode(ord('A')); # returns 65 on both | |
48 | # ASCII and EBCDIC | |
49 | # platforms | |
50 | $native = utf8::unicode_to_native(65); # returns 65 on ASCII | |
51 | # platforms; 193 on EBCDIC | |
52 | ||
ac8b87d7 EB |
53 | $flag = utf8::is_utf8($string); # since Perl 5.8.1 |
54 | $flag = utf8::valid($string); | |
973655a8 | 55 | |
a0ed51b3 LW |
56 | =head1 DESCRIPTION |
57 | ||
393fec97 | 58 | The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the |
b3419ed8 | 59 | program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based |
70122e76 | 60 | platforms). The C<no utf8> pragma tells Perl to switch back to treating |
b3419ed8 | 61 | the source text as literal bytes in the current lexical scope. |
a0ed51b3 | 62 | |
19b49582 JH |
63 | B<Do not use this pragma for anything else than telling Perl that your |
64 | script is written in UTF-8.> The utility functions described below are | |
2575c402 JW |
65 | directly usable without C<use utf8;>. |
66 | ||
67 | Because it is not possible to reliably tell UTF-8 from native 8 bit | |
68 | encodings, you need either a Byte Order Mark at the beginning of your | |
69 | source code, or C<use utf8;>, to instruct perl. | |
19b49582 | 70 | |
2575c402 JW |
71 | When UTF-8 becomes the standard source format, this pragma will |
72 | effectively become a no-op. For convenience in what follows the term | |
73 | I<UTF-X> is used to refer to UTF-8 on ASCII and ISO Latin based | |
74 | platforms and UTF-EBCDIC on EBCDIC based platforms. | |
a0ed51b3 | 75 | |
a74e8b45 JH |
76 | See also the effects of the C<-C> switch and its cousin, the |
77 | C<$ENV{PERL_UNICODE}>, in L<perlrun>. | |
78 | ||
ad0029c4 | 79 | Enabling the C<utf8> pragma has the following effect: |
a0ed51b3 | 80 | |
4ac9195f | 81 | =over 4 |
a0ed51b3 LW |
82 | |
83 | =item * | |
84 | ||
393fec97 | 85 | Bytes in the source text that have their high-bit set will be treated |
2fa62f66 | 86 | as being part of a literal UTF-X sequence. This includes most |
c20e2abd | 87 | literals such as identifier names, string constants, and constant |
8f8cf39c JH |
88 | regular expression patterns. |
89 | ||
90 | On EBCDIC platforms characters in the Latin 1 character set are | |
91 | treated as being part of a literal UTF-EBCDIC character. | |
a0ed51b3 | 92 | |
4ac9195f MS |
93 | =back |
94 | ||
ae90e350 JH |
95 | Note that if you have bytes with the eighth bit on in your script |
96 | (for example embedded Latin-1 in your string literals), C<use utf8> | |
97 | will be unhappy since the bytes are most probably not well-formed | |
2fa62f66 AT |
98 | UTF-X. If you want to have such bytes under C<use utf8>, you can disable |
99 | this pragma until the end the block (or file, if at top level) by | |
100 | C<no utf8;>. | |
ae90e350 | 101 | |
1b026014 NIS |
102 | =head2 Utility functions |
103 | ||
8800c35a JH |
104 | The following functions are defined in the C<utf8::> package by the |
105 | Perl core. You do not need to say C<use utf8> to use these and in fact | |
2f7e5073 | 106 | you should not say that unless you really want to have UTF-8 source code. |
1b026014 NIS |
107 | |
108 | =over 4 | |
109 | ||
308a4ae1 | 110 | =item * C<$num_octets = utf8::upgrade($string)> |
1b026014 | 111 | |
836ccc8e DM |
112 | Converts in-place the internal representation of the string from an octet |
113 | sequence in the native encoding (Latin-1 or EBCDIC) to I<UTF-X>. The | |
114 | logical character sequence itself is unchanged. If I<$string> is already | |
115 | stored as I<UTF-X>, then this is a no-op. Returns the | |
2575c402 JW |
116 | number of octets necessary to represent the string as I<UTF-X>. Can be |
117 | used to make sure that the UTF-8 flag is on, so that C<\w> or C<lc()> | |
118 | work as Unicode on strings containing characters in the range 0x80-0xFF | |
119 | (on ASCII and derivatives). | |
78ea37eb TS |
120 | |
121 | B<Note that this function does not handle arbitrary encodings.> | |
2575c402 JW |
122 | Therefore Encode is recommended for the general purposes; see also |
123 | L<Encode>. | |
1b026014 | 124 | |
308a4ae1 | 125 | =item * C<$success = utf8::downgrade($string[, $fail_ok])> |
1b026014 | 126 | |
730d7228 | 127 | Converts in-place the internal representation of the string from |
836ccc8e DM |
128 | I<UTF-X> to the equivalent octet sequence in the native encoding (Latin-1 |
129 | or EBCDIC). The logical character sequence itself is unchanged. If | |
130 | I<$string> is already stored as native 8 bit, then this is a no-op. Can | |
131 | be used to | |
2575c402 JW |
132 | make sure that the UTF-8 flag is off, e.g. when you want to make sure |
133 | that the substr() or length() function works with the usually faster | |
134 | byte algorithm. | |
78ea37eb | 135 | |
2575c402 | 136 | Fails if the original I<UTF-X> sequence cannot be represented in the |
ac8b87d7 | 137 | native 8 bit encoding. On failure dies or, if the value of I<$fail_ok> is |
2575c402 | 138 | true, returns false. |
78ea37eb | 139 | |
2575c402 JW |
140 | Returns true on success. |
141 | ||
142 | B<Note that this function does not handle arbitrary encodings.> | |
143 | Therefore Encode is recommended for the general purposes; see also | |
144 | L<Encode>. | |
78ea37eb | 145 | |
308a4ae1 | 146 | =item * C<utf8::encode($string)> |
1b026014 | 147 | |
2575c402 | 148 | Converts in-place the character sequence to the corresponding octet |
836ccc8e DM |
149 | sequence in I<UTF-X>. That is, every (possibly wide) character gets |
150 | replaced with a sequence of one or more characters that represent the | |
151 | individual I<UTF-X> bytes of the character. The UTF8 flag is turned off. | |
152 | Returns nothing. | |
153 | ||
291cc134 | 154 | my $a = "\x{100}"; # $a contains one character, with ord 0x100 |
ca3d51ba KW |
155 | utf8::encode($a); # $a contains two characters, with ords (on |
156 | # ASCII platforms) 0xc4 and 0x80 | |
78ea37eb TS |
157 | |
158 | B<Note that this function does not handle arbitrary encodings.> | |
2575c402 JW |
159 | Therefore Encode is recommended for the general purposes; see also |
160 | L<Encode>. | |
094ce63c | 161 | |
308a4ae1 | 162 | =item * C<$success = utf8::decode($string)> |
1b026014 | 163 | |
c8ed25e6 | 164 | Attempts to convert in-place the octet sequence encoded as I<UTF-X> to the |
836ccc8e DM |
165 | corresponding character sequence. That is, it replaces each sequence of |
166 | characters in the string whose ords represent a valid UTF-X byte | |
167 | sequence, with the corresponding single character. The UTF-8 flag is | |
168 | turned on only if the source string contains multiple-byte I<UTF-X> | |
169 | characters. If I<$string> is invalid as I<UTF-X>, returns false; | |
170 | otherwise returns true. | |
171 | ||
ca3d51ba KW |
172 | my $a = "\xc4\x80"; # $a contains two characters, with ords |
173 | # 0xc4 and 0x80 | |
174 | utf8::decode($a); # On ASCII platforms, $a contains one char, | |
175 | # with ord 0x100. On EBCDIC platforms, $a | |
176 | # is unchanged and the function returns FALSE. | |
177 | ||
178 | (C<"\xc4\x80"> is not a valid sequence of bytes in any UTF-8-encoded | |
179 | character(s) in the EBCDIC code pages that Perl supports, which is why the | |
180 | above example returns failure on them. What does decode into C<\x{100}> | |
181 | depends on the platform. It is C<"\x8C\x41"> in IBM-1047.) | |
78ea37eb TS |
182 | |
183 | B<Note that this function does not handle arbitrary encodings.> | |
2575c402 JW |
184 | Therefore Encode is recommended for the general purposes; see also |
185 | L<Encode>. | |
78ea37eb | 186 | |
ca3d51ba KW |
187 | =item * C<$unicode = utf8::native_to_unicode($code_point)> |
188 | ||
189 | This takes an unsigned integer (which represents the ordinal number of a | |
190 | character (or a code point) on the platform the program is being run on) and | |
191 | returns its Unicode equivalent value. Since ASCII platforms natively use the | |
192 | Unicode code points, this function returns its input on them. On EBCDIC | |
193 | platforms it converts from EBCIDC to Unicode. | |
194 | ||
195 | A meaningless value will currently be returned if the input is not an unsigned | |
196 | integer. | |
197 | ||
198 | =item * C<$native = utf8::unicode_to_native($code_point)> | |
199 | ||
200 | This is the inverse of C<utf8::native_to_unicode()>, converting the other | |
201 | direction. Again, on ASCII platforms, this returns its input, but on EBCDIC | |
202 | platforms it will find the native platform code point, given any Unicode one. | |
203 | ||
204 | A meaningless value will currently be returned if the input is not an unsigned | |
205 | integer. | |
206 | ||
308a4ae1 | 207 | =item * C<$flag = utf8::is_utf8($string)> |
8800c35a | 208 | |
ac8b87d7 | 209 | (Since Perl 5.8.1) Test whether I<$string> is marked internally as encoded in |
637ec54e | 210 | UTF-8. Functionally the same as Encode::is_utf8(). |
8800c35a | 211 | |
308a4ae1 | 212 | =item * C<$flag = utf8::valid($string)> |
70122e76 | 213 | |
ac8b87d7 | 214 | [INTERNAL] Test whether I<$string> is in a consistent state regarding |
9a54da5c | 215 | UTF-8. Will return true if it is well-formed UTF-8 and has the UTF-8 flag |
ac8b87d7 | 216 | on B<or> if I<$string> is held as bytes (both these states are 'consistent'). |
637ec54e | 217 | Main reason for this routine is to allow Perl's test suite to check |
8800c35a JH |
218 | that operations have left strings in a consistent state. You most |
219 | probably want to use utf8::is_utf8() instead. | |
70122e76 | 220 | |
1b026014 NIS |
221 | =back |
222 | ||
7d865a91 JH |
223 | C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is |
224 | cleared. See L<perlunicode> for more on the UTF8 flag and the C API | |
225 | functions C<sv_utf8_upgrade>, C<sv_utf8_downgrade>, C<sv_utf8_encode>, | |
094ce63c AT |
226 | and C<sv_utf8_decode>, which are wrapped by the Perl functions |
227 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and | |
7edb8f2b RGS |
228 | C<utf8::decode>. Also, the functions utf8::is_utf8, utf8::valid, |
229 | utf8::encode, utf8::decode, utf8::upgrade, and utf8::downgrade are | |
230 | actually internal, and thus always available, without a C<require utf8> | |
231 | statement. | |
f1e62f77 | 232 | |
8f8cf39c JH |
233 | =head1 BUGS |
234 | ||
235 | One can have Unicode in identifier names, but not in package/class or | |
236 | subroutine names. While some limited functionality towards this does | |
237 | exist as of Perl 5.8.0, that is more accidental than designed; use of | |
238 | Unicode for the said purposes is unsupported. | |
239 | ||
240 | One reason of this unfinishedness is its (currently) inherent | |
241 | unportability: since both package names and subroutine names may need | |
242 | to be mapped to file and directory names, the Unicode capability of | |
243 | the filesystem becomes important-- and there unfortunately aren't | |
244 | portable answers. | |
245 | ||
393fec97 | 246 | =head1 SEE ALSO |
a0ed51b3 | 247 | |
2575c402 | 248 | L<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode> |
a0ed51b3 LW |
249 | |
250 | =cut |