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1 | package utf8; |
2 | ||
3 | $utf8::hint_bits = 0x00800000; | |
4 | ||
5 | our $VERSION = '1.06'; | |
6 | ||
7 | sub import { | |
8 | $^H |= $utf8::hint_bits; | |
9 | $enc{caller()} = $_[1] if $_[1]; | |
10 | } | |
11 | ||
12 | sub unimport { | |
13 | $^H &= ~$utf8::hint_bits; | |
14 | } | |
15 | ||
16 | sub AUTOLOAD { | |
17 | require "utf8_heavy.pl"; | |
18 | goto &$AUTOLOAD if defined &$AUTOLOAD; | |
19 | require Carp; | |
20 | Carp::croak("Undefined subroutine $AUTOLOAD called"); | |
21 | } | |
22 | ||
23 | 1; | |
24 | __END__ | |
25 | ||
26 | =head1 NAME | |
27 | ||
28 | utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code | |
29 | ||
30 | =head1 SYNOPSIS | |
31 | ||
32 | use utf8; | |
33 | no utf8; | |
34 | ||
35 | # Convert a Perl scalar to/from UTF-8. | |
36 | $num_octets = utf8::upgrade($string); | |
37 | $success = utf8::downgrade($string[, FAIL_OK]); | |
38 | ||
39 | # Change the native bytes of a Perl scalar to/from UTF-8 bytes. | |
40 | utf8::encode($string); | |
41 | utf8::decode($string); | |
42 | ||
43 | $flag = utf8::is_utf8(STRING); # since Perl 5.8.1 | |
44 | $flag = utf8::valid(STRING); | |
45 | ||
46 | =head1 DESCRIPTION | |
47 | ||
48 | The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the | |
49 | program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based | |
50 | platforms). The C<no utf8> pragma tells Perl to switch back to treating | |
51 | the source text as literal bytes in the current lexical scope. | |
52 | ||
53 | This pragma is primarily a compatibility device. Perl versions | |
54 | earlier than 5.6 allowed arbitrary bytes in source code, whereas | |
55 | in future we would like to standardize on the UTF-8 encoding for | |
56 | source text. | |
57 | ||
58 | B<Do not use this pragma for anything else than telling Perl that your | |
59 | script is written in UTF-8.> The utility functions described below are | |
60 | useful for their own purposes, but they are not really part of the | |
61 | "pragmatic" effect. | |
62 | ||
63 | Until UTF-8 becomes the default format for source text, either this | |
64 | pragma or the L<encoding> pragma should be used to recognize UTF-8 | |
65 | in the source. When UTF-8 becomes the standard source format, this | |
66 | pragma will effectively become a no-op. For convenience in what | |
67 | follows the term I<UTF-X> is used to refer to UTF-8 on ASCII and ISO | |
68 | Latin based platforms and UTF-EBCDIC on EBCDIC based platforms. | |
69 | ||
70 | See also the effects of the C<-C> switch and its cousin, the | |
71 | C<$ENV{PERL_UNICODE}>, in L<perlrun>. | |
72 | ||
73 | Enabling the C<utf8> pragma has the following effect: | |
74 | ||
75 | =over 4 | |
76 | ||
77 | =item * | |
78 | ||
79 | Bytes in the source text that have their high-bit set will be treated | |
80 | as being part of a literal UTF-8 character. This includes most | |
81 | literals such as identifier names, string constants, and constant | |
82 | regular expression patterns. | |
83 | ||
84 | On EBCDIC platforms characters in the Latin 1 character set are | |
85 | treated as being part of a literal UTF-EBCDIC character. | |
86 | ||
87 | =back | |
88 | ||
89 | Note that if you have bytes with the eighth bit on in your script | |
90 | (for example embedded Latin-1 in your string literals), C<use utf8> | |
91 | will be unhappy since the bytes are most probably not well-formed | |
92 | UTF-8. If you want to have such bytes and use utf8, you can disable | |
93 | utf8 until the end the block (or file, if at top level) by C<no utf8;>. | |
94 | ||
95 | If you want to automatically upgrade your 8-bit legacy bytes to UTF-8, | |
96 | use the L<encoding> pragma instead of this pragma. For example, if | |
97 | you want to implicitly upgrade your ISO 8859-1 (Latin-1) bytes to UTF-8 | |
98 | as used in e.g. C<chr()> and C<\x{...}>, try this: | |
99 | ||
100 | use encoding "latin-1"; | |
101 | my $c = chr(0xc4); | |
102 | my $x = "\x{c5}"; | |
103 | ||
104 | In case you are wondering: yes, C<use encoding 'utf8';> works much | |
105 | the same as C<use utf8;>. | |
106 | ||
107 | =head2 Utility functions | |
108 | ||
109 | The following functions are defined in the C<utf8::> package by the | |
110 | Perl core. You do not need to say C<use utf8> to use these and in fact | |
111 | you should not say that unless you really want to have UTF-8 source code. | |
112 | ||
113 | =over 4 | |
114 | ||
115 | =item * $num_octets = utf8::upgrade($string) | |
116 | ||
117 | Converts in-place the octet sequence in the native encoding | |
118 | (Latin-1 or EBCDIC) to the equivalent character sequence in I<UTF-X>. | |
119 | I<$string> already encoded as characters does no harm. | |
120 | Returns the number of octets necessary to represent the string as I<UTF-X>. | |
121 | Can be used to make sure that the UTF-8 flag is on, | |
122 | so that C<\w> or C<lc()> work as Unicode on strings | |
123 | containing characters in the range 0x80-0xFF (on ASCII and | |
124 | derivatives). | |
125 | ||
126 | B<Note that this function does not handle arbitrary encodings.> | |
127 | Therefore I<Encode.pm> is recommended for the general purposes. | |
128 | ||
129 | Affected by the encoding pragma. | |
130 | ||
131 | =item * $success = utf8::downgrade($string[, FAIL_OK]) | |
132 | ||
133 | Converts in-place the character sequence in I<UTF-X> | |
134 | to the equivalent octet sequence in the native encoding (Latin-1 or EBCDIC). | |
135 | I<$string> already encoded as octets does no harm. | |
136 | Returns true on success. On failure dies or, if the value of | |
137 | C<FAIL_OK> is true, returns false. | |
138 | Can be used to make sure that the UTF-8 flag is off, | |
139 | e.g. when you want to make sure that the substr() or length() function | |
140 | works with the usually faster byte algorithm. | |
141 | ||
142 | B<Note that this function does not handle arbitrary encodings.> | |
143 | Therefore I<Encode.pm> is recommended for the general purposes. | |
144 | ||
145 | B<Not> affected by the encoding pragma. | |
146 | ||
147 | B<NOTE:> this function is experimental and may change | |
148 | or be removed without notice. | |
149 | ||
150 | =item * utf8::encode($string) | |
151 | ||
152 | Converts in-place the character sequence to the corresponding octet sequence | |
153 | in I<UTF-X>. The UTF-8 flag is turned off. Returns nothing. | |
154 | ||
155 | B<Note that this function does not handle arbitrary encodings.> | |
156 | Therefore I<Encode.pm> is recommended for the general purposes. | |
157 | ||
158 | =item * utf8::decode($string) | |
159 | ||
160 | Attempts to convert in-place the octet sequence in I<UTF-X> | |
161 | to the corresponding character sequence. The UTF-8 flag is turned on | |
162 | only if the source string contains multiple-byte I<UTF-X> characters. | |
163 | If I<$string> is invalid as I<UTF-X>, returns false; otherwise returns true. | |
164 | ||
165 | B<Note that this function does not handle arbitrary encodings.> | |
166 | Therefore I<Encode.pm> is recommended for the general purposes. | |
167 | ||
168 | B<NOTE:> this function is experimental and may change | |
169 | or be removed without notice. | |
170 | ||
171 | =item * $flag = utf8::is_utf8(STRING) | |
172 | ||
173 | (Since Perl 5.8.1) Test whether STRING is in UTF-8. Functionally | |
174 | the same as Encode::is_utf8(). | |
175 | ||
176 | =item * $flag = utf8::valid(STRING) | |
177 | ||
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. | |
184 | ||
185 | =back | |
186 | ||
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>, | |
190 | and C<sv_utf8_decode>, which are wrapped by the Perl functions | |
191 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and | |
192 | C<utf8::decode>. Note that in the Perl 5.8.0 and 5.8.1 implementation | |
193 | the functions utf8::is_utf8, utf8::valid, utf8::encode, utf8::decode, | |
194 | utf8::upgrade, and utf8::downgrade are always available, without a | |
195 | C<require utf8> statement-- this may change in future releases. | |
196 | ||
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 | ||
210 | =head1 SEE ALSO | |
211 | ||
212 | L<perluniintro>, L<encoding>, L<perlrun>, L<bytes>, L<perlunicode> | |
213 | ||
214 | =cut |