X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/2af1ab88da52f38a7450a6455bc28aa93c8e4e57..0f414b9566e174d41eb2dcd375172be5f19a5e0d:/lib/utf8.pm diff --git a/lib/utf8.pm b/lib/utf8.pm index 986d577..7de9f63 100644 --- a/lib/utf8.pm +++ b/lib/utf8.pm @@ -2,7 +2,7 @@ package utf8; $utf8::hint_bits = 0x00800000; -our $VERSION = '1.01'; +our $VERSION = '1.05'; sub import { $^H |= $utf8::hint_bits; @@ -16,6 +16,7 @@ sub unimport { sub AUTOLOAD { require "utf8_heavy.pl"; goto &$AUTOLOAD if defined &$AUTOLOAD; + require Carp; Carp::croak("Undefined subroutine $AUTOLOAD called"); } @@ -31,6 +32,17 @@ utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code 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 + $flag = utf8::valid(STRING); + =head1 DESCRIPTION The C pragma tells the Perl parser to allow UTF-8 in the @@ -41,12 +53,22 @@ the source text as literal bytes in the current lexical scope. This pragma is primarily a compatibility device. Perl versions earlier than 5.6 allowed arbitrary bytes in source code, whereas in future we would like to standardize on the UTF-8 encoding for -source text. Until UTF-8 becomes the default format for source -text, this pragma should be used to recognize UTF-8 in the source. -When UTF-8 becomes the standard source format, this pragma will -effectively become a no-op. For convenience in what follows the -term I is used to refer to UTF-8 on ASCII and ISO Latin based -platforms and UTF-EBCDIC on EBCDIC based platforms. +source text. + +B The utility functions described below are +useful for their own purposes, but they are not really part of the +"pragmatic" effect. + +Until UTF-8 becomes the default format for source text, either this +pragma or the L pragma should be used to recognize UTF-8 +in the source. When UTF-8 becomes the standard source format, this +pragma will effectively become a no-op. For convenience in what +follows the term I is used to refer to UTF-8 on ASCII and ISO +Latin based platforms and UTF-EBCDIC on EBCDIC based platforms. + +See also the effects of the C<-C> switch and its cousin, the +C<$ENV{PERL_UNICODE}>, in L. Enabling the C pragma has the following effect: @@ -70,54 +92,86 @@ 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. +If you want to automatically upgrade your 8-bit legacy bytes to UTF-8, +use the L 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 and C<\x{...}>, try this: + + use encoding "latin-1"; + my $c = chr(0xc4); + my $x = "\x{c5}"; + +In case you are wondering: yes, C works much +the same as C. + =head2 Utility functions The following functions are defined in the C package by the Perl core. You do not need to say C to use these and in fact -you should not unless you really want to have UTF-8 source code. +you should not say that unless you really want to have UTF-8 source code. =over 4 -=item * $num_octets = utf8::upgrade($string); +=item * $num_octets = utf8::upgrade($string) -Converts (in-place) internal representation of string to Perl's -internal I form. Returns the number of octets necessary to -represent the string as I. Can be used to make sure that the -UTF-8 flag is on, so that C<\w> or C 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 octet sequence in the native encoding +(Latin-1 or EBCDIC) to the equivalent character sequence in I. +I<$string> already encoded as characters does no harm. +Returns the number of octets necessary to represent the string as I. +Can be used to make sure that the UTF-8 flag is on, +so that C<\w> or C work as Unicode on strings +containing characters in the range 0x80-0xFF (on ASCII and +derivatives). -=item * utf8::downgrade($string[, FAIL_OK]) +B +Therefore I is recommended for the general purposes. -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 affected by the encoding -pragma. +Affected by the encoding pragma. + +=item * $success = utf8::downgrade($string[, FAIL_OK]) + +Converts in-place the character sequence in I +to the equivalent octet sequence in the native encoding (Latin-1 or EBCDIC). +I<$string> already encoded as octets does no harm. +Returns true on success. On failure dies or, if the value of +C is true, returns false. +Can be used to make sure that the UTF-8 flag is off, +e.g. when you want to make sure that the substr() or length() function +works with the usually faster byte algorithm. + +B +Therefore I is recommended for the general purposes. + +B affected by the encoding pragma. + +B this function is experimental and may change +or be removed without notice. =item * utf8::encode($string) -Converts (in-place) I<$string> from logical characters to octet -sequence representing it in Perl's I encoding. Returns -nothing. Same as Encode::encode_utf8(). Note that this should not be -used to convert a legacy byte encoding to Unicode: use Encode for -that. +Converts in-place the character sequence to the corresponding octet sequence +in I. The UTF-8 flag is turned off. Returns nothing. + +B +Therefore I is recommended for the general purposes. + +=item * utf8::decode($string) + +Attempts to convert in-place the octet sequence in I +to the corresponding character sequence. The UTF-8 flag is turned on +only if the source string contains multiple-byte I characters. +If I<$string> is invalid as I, returns false; otherwise returns true. -=item * $flag = utf8::decode($string) +B +Therefore I is recommended for the general purposes. -Attempts to convert I<$string> in-place from Perl's I 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 this function is experimental and may change +or be removed without notice. =item * $flag = utf8::is_utf8(STRING) -Test whether STRING is in UTF-8. Same as Encode::is_utf8(). +(Since Perl 5.8.1) Test whether STRING is in UTF-8. Functionally +the same as Encode::is_utf8(). =item * $flag = utf8::valid(STRING) @@ -135,8 +189,8 @@ cleared. See L for more on the UTF8 flag and the C API functions C, C, C, and C, which are wrapped by the Perl functions C, C, C and -C. Note that in the Perl 5.8.0 implementation the -functions utf8::is_utf8, utf8::valid, utf8::encode, utf8::decode, +C. 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 statement-- this may change in future releases. @@ -155,6 +209,6 @@ portable answers. =head1 SEE ALSO -L, L +L, L, L, L, L =cut