1package utf8; 2 3$utf8::hint_bits = 0x00800000; 4 5our $VERSION = '1.00'; 6 7sub import { 8 $^H |= $utf8::hint_bits; 9 $enc{caller()} = $_[1] if $_[1]; 10} 11 12sub unimport { 13 $^H &= ~$utf8::hint_bits; 14} 15 16sub AUTOLOAD { 17 require "utf8_heavy.pl"; 18 goto &$AUTOLOAD if defined &$AUTOLOAD; 19 Carp::croak("Undefined subroutine $AUTOLOAD called"); 20} 21 221; 23__END__ 24 25=head1 NAME 26 27utf8 - 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=head1 DESCRIPTION 35 36The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the 37program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based 38platforms). The C<no utf8> pragma tells Perl to switch back to treating 39the source text as literal bytes in the current lexical scope. 40 41This pragma is primarily a compatibility device. Perl versions 42earlier than 5.6 allowed arbitrary bytes in source code, whereas 43in future we would like to standardize on the UTF-8 encoding for 44source text. Until UTF-8 becomes the default format for source 45text, this pragma should be used to recognize UTF-8 in the source. 46When UTF-8 becomes the standard source format, this pragma will 47effectively become a no-op. For convenience in what follows the 48term I<UTF-X> is used to refer to UTF-8 on ASCII and ISO Latin based 49platforms and UTF-EBCDIC on EBCDIC based platforms. 50 51Enabling the C<utf8> pragma has the following effect: 52 53=over 4 54 55=item * 56 57Bytes in the source text that have their high-bit set will be treated 58as being part of a literal UTF-8 character. This includes most 59literals such as identifier names, string constants, and constant 60regular expression patterns. 61 62On EBCDIC platforms characters in the Latin 1 character set are 63treated as being part of a literal UTF-EBCDIC character. 64 65=back 66 67Note that if you have bytes with the eighth bit on in your script 68(for example embedded Latin-1 in your string literals), C<use utf8> 69will be unhappy since the bytes are most probably not well-formed 70UTF-8. If you want to have such bytes and use utf8, you can disable 71utf8 until the end the block (or file, if at top level) by C<no utf8;>. 72 73=head2 Utility functions 74 75The following functions are defined in the C<utf8::> package by the perl core. 76 77=over 4 78 79=item * $num_octets = utf8::upgrade($string); 80 81Converts (in-place) internal representation of string to Perl's internal 82I<UTF-X> form. Returns the number of octets necessary to represent 83the string as I<UTF-X>. Can be used to make sure that the 84UTF-8 flag is on, so that C<\w> or C<lc()> work as expected on strings 85containing characters in the range 0x80-0xFF. Note that this should 86not be used to convert 87a legacy byte encoding to Unicode: use Encode for that. Affected 88by the encoding pragma. 89 90=item * utf8::downgrade($string[, FAIL_OK]) 91 92Converts (in-place) internal representation of string to be un-encoded 93bytes. Returns true on success. On failure dies or, if the value of 94FAIL_OK is true, returns false. Can be used to make sure that the 95UTF-8 flag is off, e.g. when you want to make sure that the substr() 96or length() function works with the usually faster byte algorithm. 97Note that this should not be used to convert Unicode back to a legacy 98byte encoding: use Encode for that. B<Not> affected by the encoding 99pragma. 100 101=item * utf8::encode($string) 102 103Converts (in-place) I<$string> from logical characters to octet 104sequence representing it in Perl's I<UTF-X> encoding. Same as 105Encode::encode_utf8(). Note that this should not be used to convert 106a legacy byte encoding to Unicode: use Encode for that. 107 108=item * $flag = utf8::decode($string) 109 110Attempts to convert I<$string> in-place from Perl's I<UTF-X> encoding 111into logical characters. Same as Encode::decode_utf8(). Note that this 112should not be used to convert Unicode back to a legacy byte encoding: 113use Encode for that. 114 115=item * $flag = utf8::valid(STRING) 116 117[INTERNAL] Test whether STRING is in a consistent state. Will return 118true if string is held as bytes, or is well-formed UTF-8 and has the 119UTF-8 flag on. Main reason for this routine is to allow Perl's 120testsuite to check that operations have left strings in a consistent 121state. 122 123=back 124 125C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is 126cleared. See L<perlunicode> for more on the UTF8 flag and the C API 127functions C<sv_utf8_upgrade>, C<sv_utf8_downgrade>, C<sv_utf8_encode>, 128and C<sv_utf8_decode>, which are wrapped by the Perl functions 129C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and 130C<utf8::decode>. Note that in the Perl 5.8.0 implementation the 131functions utf8::valid, utf8::encode, utf8::decode, utf8::upgrade, 132and utf8::downgrade are always available, without a C<require utf8> 133statement-- this may change in future releases. 134 135=head1 BUGS 136 137One can have Unicode in identifier names, but not in package/class or 138subroutine names. While some limited functionality towards this does 139exist as of Perl 5.8.0, that is more accidental than designed; use of 140Unicode for the said purposes is unsupported. 141 142One reason of this unfinishedness is its (currently) inherent 143unportability: since both package names and subroutine names may need 144to be mapped to file and directory names, the Unicode capability of 145the filesystem becomes important-- and there unfortunately aren't 146portable answers. 147 148=head1 SEE ALSO 149 150L<perlunicode>, L<bytes> 151 152=cut 153