$utf8::hint_bits = 0x00800000;
-our $VERSION = '1.02';
+our $VERSION = '1.07';
sub import {
$^H |= $utf8::hint_bits;
sub AUTOLOAD {
require "utf8_heavy.pl";
goto &$AUTOLOAD if defined &$AUTOLOAD;
+ require Carp;
Carp::croak("Undefined subroutine $AUTOLOAD called");
}
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);
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.
-
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.
+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.
-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.
+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:
=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
+as being part of a literal UTF-X sequence. This includes most
literals such as identifier names, string constants, and constant
regular expression patterns.
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;>.
+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
=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.
+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) 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.
+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) I<$string> from logical characters to octet
-sequence representing it in Perl's I<UTF-X> encoding. Returns
-nothing. Same as Encode::encode_utf8(). Note that this should not be
-used to convert a legacy byte encoding to Unicode: use Encode for
-that.
+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)
-=item * 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.
-Attempts to convert I<$string> in-place from Perl's I<UTF-X> encoding
-into logical characters. Returns nothing. 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.
+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. Functionally
-the same as Encode::is_utf8().
+(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)
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.
+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
=head1 SEE ALSO
-L<perluniintro>, L<encoding>, L<perlunicode>, L<bytes>
+L<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode>
=cut