| 1 | package utf8; |
| 2 | |
| 3 | $utf8::hint_bits = 0x00800000; |
| 4 | |
| 5 | our $VERSION = '1.14'; |
| 6 | |
| 7 | sub import { |
| 8 | $^H |= $utf8::hint_bits; |
| 9 | } |
| 10 | |
| 11 | sub unimport { |
| 12 | $^H &= ~$utf8::hint_bits; |
| 13 | } |
| 14 | |
| 15 | sub AUTOLOAD { |
| 16 | require "utf8_heavy.pl"; |
| 17 | goto &$AUTOLOAD if defined &$AUTOLOAD; |
| 18 | require Carp; |
| 19 | Carp::croak("Undefined subroutine $AUTOLOAD called"); |
| 20 | } |
| 21 | |
| 22 | 1; |
| 23 | __END__ |
| 24 | |
| 25 | =head1 NAME |
| 26 | |
| 27 | utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code |
| 28 | |
| 29 | =head1 SYNOPSIS |
| 30 | |
| 31 | use utf8; |
| 32 | no utf8; |
| 33 | |
| 34 | # Convert the internal representation of a Perl scalar to/from UTF-8. |
| 35 | |
| 36 | $num_octets = utf8::upgrade($string); |
| 37 | $success = utf8::downgrade($string[, $fail_ok]); |
| 38 | |
| 39 | # Change each character of a Perl scalar to/from a series of |
| 40 | # characters that represent the UTF-8 bytes of each original character. |
| 41 | |
| 42 | utf8::encode($string); # "\x{100}" becomes "\xc4\x80" |
| 43 | utf8::decode($string); # "\xc4\x80" becomes "\x{100}" |
| 44 | |
| 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 | |
| 53 | $flag = utf8::is_utf8($string); # since Perl 5.8.1 |
| 54 | $flag = utf8::valid($string); |
| 55 | |
| 56 | =head1 DESCRIPTION |
| 57 | |
| 58 | The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the |
| 59 | program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based |
| 60 | platforms). The C<no utf8> pragma tells Perl to switch back to treating |
| 61 | the source text as literal bytes in the current lexical scope. |
| 62 | |
| 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 |
| 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. |
| 70 | |
| 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. |
| 75 | |
| 76 | See also the effects of the C<-C> switch and its cousin, the |
| 77 | C<$ENV{PERL_UNICODE}>, in L<perlrun>. |
| 78 | |
| 79 | Enabling the C<utf8> pragma has the following effect: |
| 80 | |
| 81 | =over 4 |
| 82 | |
| 83 | =item * |
| 84 | |
| 85 | Bytes in the source text that have their high-bit set will be treated |
| 86 | as being part of a literal UTF-X sequence. This includes most |
| 87 | literals such as identifier names, string constants, and constant |
| 88 | regular expression patterns. |
| 89 | |
| 90 | On EBCDIC platforms characters in the Latin 1 character set are |
| 91 | treated as being part of a literal UTF-EBCDIC character. |
| 92 | |
| 93 | =back |
| 94 | |
| 95 | Note that if you have bytes with the eighth bit on in your script |
| 96 | (for example embedded Latin-1 in your string literals), C<use utf8> |
| 97 | will be unhappy since the bytes are most probably not well-formed |
| 98 | UTF-X. If you want to have such bytes under C<use utf8>, you can disable |
| 99 | this pragma until the end the block (or file, if at top level) by |
| 100 | C<no utf8;>. |
| 101 | |
| 102 | =head2 Utility functions |
| 103 | |
| 104 | The following functions are defined in the C<utf8::> package by the |
| 105 | Perl core. You do not need to say C<use utf8> to use these and in fact |
| 106 | you should not say that unless you really want to have UTF-8 source code. |
| 107 | |
| 108 | =over 4 |
| 109 | |
| 110 | =item * C<$num_octets = utf8::upgrade($string)> |
| 111 | |
| 112 | Converts in-place the internal representation of the string from an octet |
| 113 | sequence in the native encoding (Latin-1 or EBCDIC) to I<UTF-X>. The |
| 114 | logical character sequence itself is unchanged. If I<$string> is already |
| 115 | stored as I<UTF-X>, then this is a no-op. Returns the |
| 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). |
| 120 | |
| 121 | B<Note that this function does not handle arbitrary encodings.> |
| 122 | Therefore Encode is recommended for the general purposes; see also |
| 123 | L<Encode>. |
| 124 | |
| 125 | =item * C<$success = utf8::downgrade($string[, $fail_ok])> |
| 126 | |
| 127 | Converts in-place the internal representation of the string from |
| 128 | I<UTF-X> to the equivalent octet sequence in the native encoding (Latin-1 |
| 129 | or EBCDIC). The logical character sequence itself is unchanged. If |
| 130 | I<$string> is already stored as native 8 bit, then this is a no-op. Can |
| 131 | be used to |
| 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. |
| 135 | |
| 136 | Fails if the original I<UTF-X> sequence cannot be represented in the |
| 137 | native 8 bit encoding. On failure dies or, if the value of I<$fail_ok> is |
| 138 | true, returns false. |
| 139 | |
| 140 | Returns true on success. |
| 141 | |
| 142 | B<Note that this function does not handle arbitrary encodings.> |
| 143 | Therefore Encode is recommended for the general purposes; see also |
| 144 | L<Encode>. |
| 145 | |
| 146 | =item * C<utf8::encode($string)> |
| 147 | |
| 148 | Converts in-place the character sequence to the corresponding octet |
| 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 | |
| 154 | my $a = "\x{100}"; # $a contains one character, with ord 0x100 |
| 155 | utf8::encode($a); # $a contains two characters, with ords (on |
| 156 | # ASCII platforms) 0xc4 and 0x80 |
| 157 | |
| 158 | B<Note that this function does not handle arbitrary encodings.> |
| 159 | Therefore Encode is recommended for the general purposes; see also |
| 160 | L<Encode>. |
| 161 | |
| 162 | =item * C<$success = utf8::decode($string)> |
| 163 | |
| 164 | Attempts to convert in-place the octet sequence encoded as I<UTF-X> to the |
| 165 | corresponding character sequence. That is, it replaces each sequence of |
| 166 | characters in the string whose ords represent a valid UTF-X byte |
| 167 | sequence, with the corresponding single character. The UTF-8 flag is |
| 168 | turned on only if the source string contains multiple-byte I<UTF-X> |
| 169 | characters. If I<$string> is invalid as I<UTF-X>, returns false; |
| 170 | otherwise returns true. |
| 171 | |
| 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, $a |
| 176 | # is unchanged and the function returns FALSE. |
| 177 | |
| 178 | (C<"\xc4\x80"> is not a valid sequence of bytes in any UTF-8-encoded |
| 179 | character(s) in the EBCDIC code pages that Perl supports, which is why the |
| 180 | above example returns failure on them. What does decode into C<\x{100}> |
| 181 | depends on the platform. It is C<"\x8C\x41"> in IBM-1047.) |
| 182 | |
| 183 | B<Note that this function does not handle arbitrary encodings.> |
| 184 | Therefore Encode is recommended for the general purposes; see also |
| 185 | L<Encode>. |
| 186 | |
| 187 | =item * C<$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($code_point)> |
| 199 | |
| 200 | This is the inverse of C<utf8::native_to_unicode()>, converting the other |
| 201 | direction. Again, on ASCII platforms, this returns its input, but on EBCDIC |
| 202 | platforms it will find the native platform code point, given any Unicode one. |
| 203 | |
| 204 | A meaningless value will currently be returned if the input is not an unsigned |
| 205 | integer. |
| 206 | |
| 207 | =item * C<$flag = utf8::is_utf8($string)> |
| 208 | |
| 209 | (Since Perl 5.8.1) Test whether I<$string> is marked internally as encoded in |
| 210 | UTF-8. Functionally the same as Encode::is_utf8(). |
| 211 | |
| 212 | =item * C<$flag = utf8::valid($string)> |
| 213 | |
| 214 | [INTERNAL] Test whether I<$string> is in a consistent state regarding |
| 215 | UTF-8. Will return true if it is well-formed UTF-8 and has the UTF-8 flag |
| 216 | on B<or> if I<$string> is held as bytes (both these states are 'consistent'). |
| 217 | Main reason for this routine is to allow Perl's test suite to check |
| 218 | that operations have left strings in a consistent state. You most |
| 219 | probably want to use utf8::is_utf8() instead. |
| 220 | |
| 221 | =back |
| 222 | |
| 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>, |
| 226 | and C<sv_utf8_decode>, which are wrapped by the Perl functions |
| 227 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and |
| 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. |
| 232 | |
| 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 | |
| 246 | =head1 SEE ALSO |
| 247 | |
| 248 | L<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode> |
| 249 | |
| 250 | =cut |