diff options
Diffstat (limited to 'Master/tlpkg/tlperl.straw/lib/utf8.pm')
-rwxr-xr-x | Master/tlpkg/tlperl.straw/lib/utf8.pm | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/Master/tlpkg/tlperl.straw/lib/utf8.pm b/Master/tlpkg/tlperl.straw/lib/utf8.pm new file mode 100755 index 00000000000..a985021f32a --- /dev/null +++ b/Master/tlpkg/tlperl.straw/lib/utf8.pm @@ -0,0 +1,198 @@ +package utf8; + +$utf8::hint_bits = 0x00800000; + +our $VERSION = '1.07'; + +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; + require Carp; + 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; + + # Convert a Perl scalar to/from UTF-8. + $num_octets = utf8::upgrade($string); + $success = utf8::downgrade($string[, FAIL_OK]); + + # Change the native bytes of a Perl scalar to/from UTF-8 bytes. + utf8::encode($string); + utf8::decode($string); + + $flag = utf8::is_utf8(STRING); # since Perl 5.8.1 + $flag = utf8::valid(STRING); + +=head1 DESCRIPTION + +The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the +program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based +platforms). The C<no utf8> pragma tells Perl to switch back to treating +the source text as literal bytes in the current lexical scope. + +B<Do not use this pragma for anything else than telling Perl that your +script is written in UTF-8.> The utility functions described below are +directly usable without C<use utf8;>. + +Because it is not possible to reliably tell UTF-8 from native 8 bit +encodings, you need either a Byte Order Mark at the beginning of your +source code, or C<use utf8;>, to instruct perl. + +When UTF-8 becomes the standard source format, this pragma will +effectively become a no-op. For convenience in what follows the term +I<UTF-X> is used to refer to UTF-8 on ASCII and ISO Latin based +platforms and UTF-EBCDIC on EBCDIC based platforms. + +See also the effects of the C<-C> switch and its cousin, the +C<$ENV{PERL_UNICODE}>, in L<perlrun>. + +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-X sequence. 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-X. If you want to have such bytes under C<use utf8>, you can disable +this pragma 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. You do not need to say C<use utf8> to use these and in fact +you should not say that unless you really want to have UTF-8 source code. + +=over 4 + +=item * $num_octets = utf8::upgrade($string) + +Converts in-place the internal octet sequence in the native encoding +(Latin-1 or EBCDIC) to the equivalent character sequence in I<UTF-X>. +I<$string> already encoded as characters does no harm. 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 Unicode on strings containing characters in the range 0x80-0xFF +(on ASCII and derivatives). + +B<Note that this function does not handle arbitrary encodings.> +Therefore Encode is recommended for the general purposes; see also +L<Encode>. + +=item * $success = utf8::downgrade($string[, FAIL_OK]) + +Converts in-place the internal octet sequence in I<UTF-X> to the +equivalent octet sequence in the native encoding (Latin-1 or EBCDIC). +I<$string> already encoded as native 8 bit does no harm. Can be used to +make sure that the UTF-8 flag is off, e.g. when you want to make sure +that the substr() or length() function works with the usually faster +byte algorithm. + +Fails if the original I<UTF-X> sequence cannot be represented in the +native 8 bit encoding. On failure dies or, if the value of C<FAIL_OK> is +true, returns false. + +Returns true on success. + +B<Note that this function does not handle arbitrary encodings.> +Therefore Encode is recommended for the general purposes; see also +L<Encode>. + +=item * utf8::encode($string) + +Converts in-place the character sequence to the corresponding octet +sequence in I<UTF-X>. The UTF8 flag is turned off, so that after this +operation, the string is a byte string. Returns nothing. + +B<Note that this function does not handle arbitrary encodings.> +Therefore Encode is recommended for the general purposes; see also +L<Encode>. + +=item * $success = utf8::decode($string) + +Attempts to convert in-place the octet sequence in I<UTF-X> to the +corresponding character sequence. The UTF-8 flag is turned on only if +the source string contains multiple-byte I<UTF-X> characters. If +I<$string> is invalid as I<UTF-X>, returns false; otherwise returns +true. + +B<Note that this function does not handle arbitrary encodings.> +Therefore Encode is recommended for the general purposes; see also +L<Encode>. + +=item * $flag = utf8::is_utf8(STRING) + +(Since Perl 5.8.1) Test whether STRING is in UTF-8 internally. +Functionally the same as Encode::is_utf8(). + +=item * $flag = utf8::valid(STRING) + +[INTERNAL] Test whether STRING is in a consistent state regarding +UTF-8. Will return true is well-formed UTF-8 and has the UTF-8 flag +on B<or> if string is held as bytes (both these states are 'consistent'). +Main reason for this routine is to allow Perl's testsuite to check +that operations have left strings in a consistent state. You most +probably want to use utf8::is_utf8() instead. + +=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>. Also, the functions utf8::is_utf8, utf8::valid, +utf8::encode, utf8::decode, utf8::upgrade, and utf8::downgrade are +actually internal, and thus always available, without a C<require utf8> +statement. + +=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<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode> + +=cut |