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Diffstat (limited to 'Master/xemtex/perl/lib/utf8.pm')
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diff --git a/Master/xemtex/perl/lib/utf8.pm b/Master/xemtex/perl/lib/utf8.pm new file mode 100644 index 00000000000..5a37aecba87 --- /dev/null +++ b/Master/xemtex/perl/lib/utf8.pm @@ -0,0 +1,152 @@ +package utf8; + +$utf8::hint_bits = 0x00800000; + +our $VERSION = '1.00'; + +sub import { + $^H |= $utf8::hint_bits; + $enc{caller()} = $_[1] if $_[1]; +} + +sub unimport { + $^H &= ~$utf8::hint_bits; +} + +sub AUTOLOAD { + require "utf8_heavy.pl"; + goto &$AUTOLOAD if defined &$AUTOLOAD; + Carp::croak("Undefined subroutine $AUTOLOAD called"); +} + +1; +__END__ + +=head1 NAME + +utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code + +=head1 SYNOPSIS + + use utf8; + no utf8; + +=head1 DESCRIPTION + +The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the +program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based +platforms). The C<no utf8> pragma tells Perl to switch back to treating +the source text as literal bytes in the current lexical scope. + +This pragma is primarily a compatibility device. Perl versions +earlier than 5.6 allowed arbitrary bytes in source code, whereas +in future we would like to standardize on the UTF-8 encoding for +source text. Until UTF-8 becomes the default format for source +text, this pragma should be used to recognize UTF-8 in the source. +When UTF-8 becomes the standard source format, this pragma will +effectively become a no-op. For convenience in what follows the +term I<UTF-X> is used to refer to UTF-8 on ASCII and ISO Latin based +platforms and UTF-EBCDIC on EBCDIC based platforms. + +Enabling the C<utf8> pragma has the following effect: + +=over 4 + +=item * + +Bytes in the source text that have their high-bit set will be treated +as being part of a literal UTF-8 character. This includes most +literals such as identifier names, string constants, and constant +regular expression patterns. + +On EBCDIC platforms characters in the Latin 1 character set are +treated as being part of a literal UTF-EBCDIC character. + +=back + +Note that if you have bytes with the eighth bit on in your script +(for example embedded Latin-1 in your string literals), C<use utf8> +will be unhappy since the bytes are most probably not well-formed +UTF-8. If you want to have such bytes and use utf8, you can disable +utf8 until the end the block (or file, if at top level) by C<no utf8;>. + +=head2 Utility functions + +The following functions are defined in the C<utf8::> package by the perl core. + +=over 4 + +=item * $num_octets = utf8::upgrade($string); + +Converts (in-place) internal representation of string to Perl's internal +I<UTF-X> form. Returns the number of octets necessary to represent +the string as I<UTF-X>. Can be used to make sure that the +UTF-8 flag is on, so that C<\w> or C<lc()> work as expected on strings +containing characters in the range 0x80-0xFF. Note that this should +not be used to convert +a legacy byte encoding to Unicode: use Encode for that. Affected +by the encoding pragma. + +=item * utf8::downgrade($string[, FAIL_OK]) + +Converts (in-place) internal representation of string to be un-encoded +bytes. Returns true on success. On failure dies or, if the value of +FAIL_OK is true, returns false. Can be used to make sure that the +UTF-8 flag is off, e.g. when you want to make sure that the substr() +or length() function works with the usually faster byte algorithm. +Note that this should not be used to convert Unicode back to a legacy +byte encoding: use Encode for that. B<Not> affected by the encoding +pragma. + +=item * utf8::encode($string) + +Converts (in-place) I<$string> from logical characters to octet +sequence representing it in Perl's I<UTF-X> encoding. Same as +Encode::encode_utf8(). Note that this should not be used to convert +a legacy byte encoding to Unicode: use Encode for that. + +=item * $flag = utf8::decode($string) + +Attempts to convert I<$string> in-place from Perl's I<UTF-X> encoding +into logical characters. Same as Encode::decode_utf8(). Note that this +should not be used to convert Unicode back to a legacy byte encoding: +use Encode for that. + +=item * $flag = utf8::valid(STRING) + +[INTERNAL] Test whether STRING is in a consistent state. Will return +true if string is held as bytes, or is well-formed UTF-8 and has the +UTF-8 flag on. Main reason for this routine is to allow Perl's +testsuite to check that operations have left strings in a consistent +state. + +=back + +C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is +cleared. See L<perlunicode> for more on the UTF8 flag and the C API +functions C<sv_utf8_upgrade>, C<sv_utf8_downgrade>, C<sv_utf8_encode>, +and C<sv_utf8_decode>, which are wrapped by the Perl functions +C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and +C<utf8::decode>. Note that in the Perl 5.8.0 implementation the +functions utf8::valid, utf8::encode, utf8::decode, utf8::upgrade, +and utf8::downgrade are always available, without a C<require utf8> +statement-- this may change in future releases. + +=head1 BUGS + +One can have Unicode in identifier names, but not in package/class or +subroutine names. While some limited functionality towards this does +exist as of Perl 5.8.0, that is more accidental than designed; use of +Unicode for the said purposes is unsupported. + +One reason of this unfinishedness is its (currently) inherent +unportability: since both package names and subroutine names may need +to be mapped to file and directory names, the Unicode capability of +the filesystem becomes important-- and there unfortunately aren't +portable answers. + +=head1 SEE ALSO + +L<perlunicode>, L<bytes> + +=cut |