package utf8;
+$utf8::hint_bits = 0x00800000;
+
+our $VERSION = '1.03';
+
sub import {
- $^H |= 0x00800000;
+ $^H |= $utf8::hint_bits;
$enc{caller()} = $_[1] if $_[1];
}
sub unimport {
- $^H &= ~0x00800000;
+ $^H &= ~$utf8::hint_bits;
}
sub AUTOLOAD {
require "utf8_heavy.pl";
- goto &$AUTOLOAD;
+ goto &$AUTOLOAD if defined &$AUTOLOAD;
+ Carp::croak("Undefined subroutine $AUTOLOAD called");
}
1;
=head1 NAME
-utf8 - Perl pragma to enable/disable UTF-8 in source code
+utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code
=head1 SYNOPSIS
use utf8;
no utf8;
-=head1 DESCRIPTION
+ # Convert a Perl scalar to/from UTF-8.
+ $num_octets = utf8::upgrade($string);
+ $success = utf8::downgrade($string[, FAIL_OK]);
-WARNING: The implementation of Unicode support in Perl is incomplete.
-Expect sudden and unannounced changes!
+ # 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
+ $flag = utf8::valid(STRING);
+
+=head1 DESCRIPTION
The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the
-program text in the current lexical scope. The C<no utf8> pragma
-tells Perl to switch back to treating the source text as literal
-bytes in the current lexical scope.
+program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based
+platforms). The C<no utf8> pragma tells Perl to switch back to treating
+the source text as literal bytes in the current lexical scope.
This pragma is primarily a compatibility device. Perl versions
earlier than 5.6 allowed arbitrary bytes in source code, whereas
in future we would like to standardize on the UTF-8 encoding for
-source text. Until UTF-8 becomes the default format for source
-text, this pragma should be used to recognize UTF-8 in the source.
-When UTF-8 becomes the standard source format, this pragma will
-effectively become a no-op.
+source text.
-Enabling the C<utf8> pragma has the following effects:
+B<Do not use this pragma for anything else than telling Perl that your
+script is written in UTF-8.> The utility functions described below are
+useful for their own purposes, but they are not really part of the
+"pragmatic" effect.
-=over
+Until UTF-8 becomes the default format for source text, either this
+pragma or the L</encoding> pragma should be used to recognize UTF-8
+in the source. When UTF-8 becomes the standard source format, this
+pragma will effectively become a no-op. For convenience in what
+follows the term I<UTF-X> is used to refer to UTF-8 on ASCII and ISO
+Latin based platforms and UTF-EBCDIC on EBCDIC based platforms.
-=item *
+See also the effects of the C<-C> switch and its cousin, the
+C<$ENV{PERL_UNICODE}>, in L<perlrun>.
-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 identifiers, string constants, constant regular expression patterns
-and package names.
+Enabling the C<utf8> pragma has the following effect:
-=item *
+=over 4
-In the absence of inputs marked as UTF-8, regular expressions within the
-scope of this pragma will default to using character semantics instead
-of byte semantics.
+=item *
- @bytes_or_chars = split //, $data; # may split to bytes if data
- # $data isn't UTF-8
- {
- use utf8; # force char semantics
- @chars = split //, $data; # splits characters
- }
+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;>.
+
+If you want to automatically upgrade your 8-bit legacy bytes to UTF-8,
+use the L</encoding> pragma instead of this pragma. For example, if
+you want to implicitly upgrade your ISO 8859-1 (Latin-1) bytes to UTF-8
+as used in e.g. C<chr()> and C<\x{...}>, try this:
+
+ use encoding "latin-1";
+ my $c = chr(0xc4);
+ my $x = "\x{c5}";
+
+In case you are wondering: yes, C<use encoding 'utf8';> works much
+the same as C<use 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) 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 (oon ASCII and
+derivatives). 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 * $success = utf8::downgrade($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($string)
+
+Converts in-place the octets of the I<$string> to the octet sequence
+in Perl's I<UTF-X> encoding. Returns nothing. B<Note that this does
+not change the "type" of I<$string> to UTF-8>, and that this handles
+only ISO 8859-1 (or EBCDIC) as the source character set. Therefore
+this should not be used to convert a legacy 8-bit encoding to Unicode:
+use Encode::decode() for that. In the very limited case of wanting to
+handle just ISO 8859-1 (or EBCDIC), you could use utf8::upgrade().
+
+=item * utf8::decode($string)
+
+Attempts to convert I<$string> in-place from Perl's I<UTF-X> encoding
+into octets. Returns nothing. B<Note that this does not change the
+"type" of <$string> from UTF-8>, and that this handles only ISO 8859-1
+(or EBCDIC) as the destination character set. Therefore this should
+not be used to convert Unicode back to a legacy 8-bit encoding:
+use Encode::encode() for that. In the very limited case of wanting
+to handle just ISO 8859-1 (or EBCDIC), you could use utf8::downgrade().
+
+=item * $flag = utf8::is_utf8(STRING)
+
+(Since Perl 5.8.1) Test whether STRING is in UTF-8. 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>. Note that in the Perl 5.8.0 and 5.8.1 implementation
+the functions utf8::is_utf8, 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<byte>
+L<perluniintro>, L<encoding>, L<perlrun>, L<bytes>, L<perlunicode>
=cut