X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/bc1767aa26319247b21d0a61f937739a53a27082..ebf06983127fdec6e5f31c7ecc2d3a3ac991cfa2:/lib/utf8.pm diff --git a/lib/utf8.pm b/lib/utf8.pm index 1176240..607c59d 100644 --- a/lib/utf8.pm +++ b/lib/utf8.pm @@ -2,7 +2,7 @@ package utf8; $utf8::hint_bits = 0x00800000; -our $VERSION = '1.16'; +our $VERSION = '1.22'; sub import { $^H |= $utf8::hint_bits; @@ -13,7 +13,6 @@ sub unimport { } sub AUTOLOAD { - require "utf8_heavy.pl"; goto &$AUTOLOAD if defined &$AUTOLOAD; require Carp; Carp::croak("Undefined subroutine $AUTOLOAD called"); @@ -47,8 +46,9 @@ utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code $unicode = utf8::native_to_unicode(ord('A')); # returns 65 on both # ASCII and EBCDIC # platforms - $native = utf8::unicode_to_native(65); # returns 65 on ASCII - # platforms; 193 on EBCDIC + $native = utf8::unicode_to_native(65); # returns 65 on ASCII + # platforms; 193 on + # EBCDIC $flag = utf8::is_utf8($string); # since Perl 5.8.1 $flag = utf8::valid($string); @@ -56,9 +56,11 @@ utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code =head1 DESCRIPTION The C pragma tells the Perl parser to allow UTF-8 in the -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. +program text in the current lexical scope. The C pragma tells Perl +to switch back to treating the source text as literal bytes in the current +lexical scope. (On EBCDIC platforms, technically it is allowing UTF-EBCDIC, +and not UTF-8, but this distinction is academic, so in this document the term +UTF-8 is used to mean both). B The utility functions described below are @@ -69,9 +71,7 @@ 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 -platforms and UTF-EBCDIC on EBCDIC based platforms. +effectively become a no-op. See also the effects of the C<-C> switch and its cousin, the C environment variable, in L. @@ -82,22 +82,17 @@ 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-X sequence. This includes most +Bytes in the source text that are not in the ASCII character set will be +treated as being part of a literal UTF-8 sequence. 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 -will be unhappy since the bytes are most probably not well-formed -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. +Note that if you have non-ASCII, non-UTF-8 bytes in your script (for example +embedded Latin-1 in your string literals), C will be unhappy. 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 @@ -109,80 +104,104 @@ you should not say that unless you really want to have UTF-8 source code. =item * C<$num_octets = utf8::upgrade($string)> +(Since Perl v5.8.0) Converts in-place the internal representation of the string from an octet -sequence in the native encoding (Latin-1 or EBCDIC) to I. The +sequence in the native encoding (Latin-1 or EBCDIC) to UTF-8. The logical character sequence itself is unchanged. If I<$string> is already -stored as I, then this is a no-op. Returns the -number of octets necessary to represent the string as I. Can be -used to make sure that the UTF-8 flag is on, so that C<\w> or C -work as Unicode on strings containing characters in the range 0x80-0xFF -(on ASCII and derivatives). +upgraded, then this is a no-op. Returns the +number of octets necessary to represent the string as UTF-8. -B -Therefore Encode is recommended for the general purposes; see also -L. +If your code needs to be compatible with versions of perl without +C, you can force Unicode semantics on +a given string: -=item * C<$success = utf8::downgrade($string[, $fail_ok])> + # force unicode semantics for $string without the + # "unicode_strings" feature + utf8::upgrade($string); -Converts in-place the internal representation of the string from -I 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. +For example: -Fails if the original I sequence cannot be represented in the + # without explicit or implicit use feature 'unicode_strings' + my $x = "\xDF"; # LATIN SMALL LETTER SHARP S + $x =~ /ss/i; # won't match + my $y = uc($x); # won't convert + utf8::upgrade($x); + $x =~ /ss/i; # matches + my $z = uc($x); # converts to "SS" + +B; +use L instead. + +=item * C<$success = utf8::downgrade($string[, $fail_ok])> + +(Since Perl v5.8.0) +Converts in-place the internal representation of the string from UTF-8 to the +equivalent octet sequence in the native encoding (Latin-1 or EBCDIC). The +logical character sequence itself is unchanged. If I<$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 UTF-8 sequence cannot be represented in the native 8 bit encoding. On failure dies or, if the value of I<$fail_ok> is true, returns false. Returns true on success. -B -Therefore Encode is recommended for the general purposes; see also -L. +If your code expects an octet sequence this can be used to validate +that you've received one: + + # throw an exception if not representable as octets + utf8::downgrade($string) + + # or do your own error handling + utf8::downgrade($string, 1) or die "string must be octets"; + +B; +use L instead. =item * C +(Since Perl v5.8.0) Converts in-place the character sequence to the corresponding octet -sequence in I. That is, every (possibly wide) character gets -replaced with a sequence of one or more characters that represent the -individual I bytes of the character. The UTF8 flag is turned off. +sequence in Perl's extended UTF-8. That is, every (possibly wide) character +gets replaced with a sequence of one or more characters that represent the +individual UTF-8 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 (on - # ASCII platforms) 0xc4 and 0x80 + my $x = "\x{100}"; # $x contains one character, with ord 0x100 + utf8::encode($x); # $x contains two characters, with ords (on + # ASCII platforms) 0xc4 and 0x80. On EBCDIC + # 1047, this would instead be 0x8C and 0x41. + +Similar to: + + use Encode; + $x = Encode::encode("utf8", $x); -B -Therefore Encode is recommended for the general purposes; see also -L. +B; +use L instead. =item * C<$success = utf8::decode($string)> -Attempts to convert in-place the octet sequence encoded as I to the -corresponding character sequence. That is, it replaces each sequence of -characters in the string whose ords represent a valid UTF-X byte -sequence, with the corresponding single character. The UTF-8 flag is -turned on only if the source string contains multiple-byte I -characters. If I<$string> is invalid as I, returns false; +(Since Perl v5.8.0) +Attempts to convert in-place the octet sequence encoded in Perl's extended +UTF-8 to the corresponding character sequence. That is, it replaces each +sequence of characters in the string whose ords represent a valid (extended) +UTF-8 byte sequence, with the corresponding single character. The UTF-8 flag +is turned on only if the source string contains multiple-byte UTF-8 +characters. If I<$string> is invalid as extended UTF-8, returns false; otherwise returns true. - my $a = "\xc4\x80"; # $a contains two characters, with ords + my $x = "\xc4\x80"; # $x contains two characters, with ords # 0xc4 and 0x80 - utf8::decode($a); # On ASCII platforms, $a contains one char, - # with ord 0x100. On EBCDIC platforms, $a - # is unchanged and the function returns FALSE. - -(C<"\xc4\x80"> is not a valid sequence of bytes in any UTF-8-encoded -character(s) in the EBCDIC code pages that Perl supports, which is why the -above example returns failure on them. What does decode into C<\x{100}> -depends on the platform. It is C<"\x8C\x41"> in IBM-1047.) + utf8::decode($x); # On ASCII platforms, $x contains one char, + # with ord 0x100. Since these bytes aren't + # legal UTF-EBCDIC, on EBCDIC platforms, $x is + # unchanged and the function returns FALSE. -B -Therefore Encode is recommended for the general purposes; see also -L. +B; +use L instead. =item * C<$unicode = utf8::native_to_unicode($code_point)> @@ -215,41 +234,50 @@ platforms, so there is no performance hit in using it there. =item * C<$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(). +UTF-8. Functionally the same as C. + +Typically only necessary for debugging and testing, if you need to +dump the internals of an SV, L Dump() +provides more detail in a compact form. + +If you still think you need this outside of debugging, testing or +dealing with filenames, you should probably read L and +L. + +Don't use this flag as a marker to distinguish character and binary +data: that should be decided for each variable when you write your +code. + +To force unicode semantics in code portable to perl 5.8 and 5.10, call +C unconditionally. =item * C<$flag = utf8::valid($string)> [INTERNAL] Test whether I<$string> is in a consistent state regarding -UTF-8. Will return true if it is well-formed UTF-8 and has the UTF-8 flag +UTF-8. Will return true if it is well-formed Perl extended UTF-8 and has the +UTF-8 flag on B if I<$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. +The main reason for this routine is to allow Perl's test suite to check +that operations have left strings in a consistent state. =back C is like C, but the UTF8 flag is -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 +cleared. See L, and the C API +functions C>, +C>, C>, +and C>, which are wrapped by the Perl functions C, C, C and -C. Also, the functions utf8::is_utf8, utf8::valid, -utf8::encode, utf8::decode, utf8::upgrade, and utf8::downgrade are +C. Also, the functions C, C, +C, C, C, and C are actually internal, and thus always available, without a C 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. +Some filesystems may not support UTF-8 file names, or they may be supported +incompatibly with Perl. Therefore UTF-8 names that are visible to the +filesystem, such as module names may not work. =head1 SEE ALSO