X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2Futf8.pm;h=a985021f32a40f2857b6eb4d5e0a59decbc7b376;hb=a06bfbf46ad8e21060b59ed409ba2f87fbfcdc35;hp=0c8a99135db3e175e4a5998d01649fba000eb9bb;hpb=6e37fd2a54b1a286397ea047abb89aad1f47cd8d;p=p5sagit%2Fp5-mst-13.2.git diff --git a/lib/utf8.pm b/lib/utf8.pm index 0c8a991..a985021 100644 --- a/lib/utf8.pm +++ b/lib/utf8.pm @@ -2,7 +2,7 @@ package utf8; $utf8::hint_bits = 0x00800000; -our $VERSION = '1.00'; +our $VERSION = '1.07'; 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 + $flag = utf8::valid(STRING); + =head1 DESCRIPTION The C pragma tells the Perl parser to allow UTF-8 in the @@ -38,16 +50,22 @@ program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based platforms). The C pragma tells Perl to switch back to treating the source text as literal bytes in the current lexical scope. -This pragma is primarily a compatibility device. Perl versions -earlier than 5.6 allowed arbitrary bytes in source code, whereas -in future we would like to standardize on the UTF-8 encoding for -source text. Until UTF-8 becomes the default format for source -text, this pragma should be used to recognize UTF-8 in the source. +B The utility functions described below are +directly usable without C. + +Because it is not possible to reliably tell UTF-8 from native 8 bit +encodings, you need either a Byte Order Mark at the beginning of your +source code, or C, to instruct perl. + When UTF-8 becomes the standard source format, this pragma will -effectively become a no-op. For convenience in what follows the -term I is used to refer to UTF-8 on ASCII and ISO Latin based +effectively become a no-op. For convenience in what follows the term +I is used to refer to UTF-8 on ASCII and ISO Latin based platforms and UTF-EBCDIC on EBCDIC based platforms. +See also the effects of the C<-C> switch and its cousin, the +C<$ENV{PERL_UNICODE}>, in L. + Enabling the C pragma has the following effect: =over 4 @@ -55,7 +73,7 @@ Enabling the C 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. @@ -67,57 +85,77 @@ treated as being part of a literal UTF-EBCDIC character. Note that if you have bytes with the eighth bit on in your script (for example embedded Latin-1 in your string literals), C 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. +UTF-X. If you want to have such bytes under C, you can disable +this pragma until the end the block (or file, if at top level) by +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 internal 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 Encode is recommended for the general purposes; see also +L. -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. +=item * $success = utf8::downgrade($string[, FAIL_OK]) + +Converts in-place the internal octet sequence in I to the +equivalent octet sequence in the native encoding (Latin-1 or EBCDIC). +I<$string> already encoded as native 8 bit does no harm. Can be used to +make sure that the UTF-8 flag is off, e.g. when you want to make sure +that the substr() or length() function works with the usually faster +byte algorithm. + +Fails if the original I sequence cannot be represented in the +native 8 bit encoding. On failure dies or, if the value of C is +true, returns false. + +Returns true on success. + +B +Therefore Encode is recommended for the general purposes; see also +L. =item * utf8::encode($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 UTF8 flag is turned off, so that after this +operation, the string is a byte string. Returns nothing. + +B +Therefore Encode is recommended for the general purposes; see also +L. + +=item * $success = utf8::decode($string) -=item * $flag = utf8::decode($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<$string> is invalid as I, returns false; otherwise returns +true. -Attempts to convert I<$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 +Therefore Encode is recommended for the general purposes; see also +L. =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 internally. +Functionally the same as Encode::is_utf8(). =item * $flag = utf8::valid(STRING) @@ -135,10 +173,10 @@ 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, -utf8::upgrade, and utf8::downgrade are always available, without a -C statement-- this may change in future releases. +C. 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 +statement. =head1 BUGS @@ -155,6 +193,6 @@ portable answers. =head1 SEE ALSO -L, L +L, L, L, L, L =cut