$utf8::hint_bits = 0x00800000;
+our $VERSION = '1.12';
+
sub import {
$^H |= $utf8::hint_bits;
- $enc{caller()} = $_[1] if $_[1];
}
sub unimport {
sub AUTOLOAD {
require "utf8_heavy.pl";
- goto &$AUTOLOAD;
+ goto &$AUTOLOAD if defined &$AUTOLOAD;
+ require Carp;
+ 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;
+ use utf8;
+ no utf8;
-=head1 DESCRIPTION
+ # Convert the internal representation of a Perl scalar to/from UTF-8.
+
+ $num_octets = utf8::upgrade($string);
+ $success = utf8::downgrade($string[, $fail_ok]);
+
+ # Change each character of a Perl scalar to/from a series of
+ # characters that represent the UTF-8 bytes of each original character.
-WARNING: The implementation of Unicode support in Perl is incomplete.
-Expect sudden and unannounced changes!
+ utf8::encode($string); # "\x{100}" becomes "\xc4\x80"
+ utf8::decode($string); # "\xc4\x80" becomes "\x{100}"
+
+ $flag = utf8::is_utf8($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.
-
-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.
+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.
+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 effects:
+See also the effects of the C<-C> switch and its cousin, the
+C<$ENV{PERL_UNICODE}>, in L<perlrun>.
-=over
+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 identifiers, string constants, constant regular expression patterns
-and package names.
+as being part of a literal UTF-X sequence. This includes most
+literals such as identifier names, string constants, and constant
+regular expression patterns.
-=item *
+On EBCDIC platforms characters in the Latin 1 character set are
+treated as being part of a literal UTF-EBCDIC character.
+
+=back
-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.
+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.
- @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
- }
+=over 4
+
+=item * $num_octets = utf8::upgrade($string)
+
+Converts in-place the internal representation of the string from an octet
+sequence in the native encoding (Latin-1 or EBCDIC) to I<UTF-X>. The
+logical character sequence itself is unchanged. If I<$string> is already
+stored as I<UTF-X>, then this is a no-op. 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[, $fail_ok])
+
+Converts in-place the internal representation of the string from
+I<UTF-X> to the equivalent octet sequence in the native encoding (Latin-1
+or EBCDIC). The logical character sequence itself is unchanged. If
+I<$string> is already stored as native 8 bit, then this is a no-op. 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 I<$fail_ok> is
+true, returns false.
+
+Returns true on success.
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore Encode is recommended for the general purposes; see also
+L<Encode>.
+
+=item * utf8::encode($string)
+
+Converts in-place the character sequence to the corresponding octet
+sequence in I<UTF-X>. That is, every (possibly wide) character gets
+replaced with a sequence of one or more characters that represent the
+individual I<UTF-X> bytes of the character. The UTF8 flag is turned off.
+Returns nothing.
+
+ my $a = "\x{100}"; # $a contains one character, with ord 0x100
+ utf8::encode($a); # $a contains two characters, with ords 0xc4 and
+ # 0x80
+
+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. That is, it replaces each sequence of
+characters in the string whose ords represent a valid UTF-X byte
+sequence, with the corresponding single character. 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.
+
+ my $a = "\xc4\x80"; # $a contains two characters, with ords
+ # 0xc4 and 0x80
+ utf8::decode($a); # $a contains one character, with ord 0x100
+
+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 I<$string> is marked internally as encoded in
+UTF-8. Functionally the same as Encode::is_utf8().
+
+=item * $flag = utf8::valid($string)
+
+[INTERNAL] Test whether I<$string> is in a consistent state regarding
+UTF-8. Will return true if it is well-formed UTF-8 and has the UTF-8 flag
+on B<or> if I<$string> is held as bytes (both these states are 'consistent').
+Main reason for this routine is to allow Perl's test suite 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<perlunicode>, L<bytes>
+L<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode>
=cut
https://perl5.git.perl.org / perl5.git / blobdiff