diff options
author | Norbert Preining <preining@logic.at> | 2010-05-12 16:54:37 +0000 |
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committer | Norbert Preining <preining@logic.at> | 2010-05-12 16:54:37 +0000 |
commit | 661c41a09e39a182865e0b51e34cc995a0dc96e8 (patch) | |
tree | 2f79bb1406e22fdcb2587be8ffda6c0c609d7932 /Master/tlpkg/tlperl/lib/encoding.pm | |
parent | b645030efc22e13c2498a1522083634ab91b2de1 (diff) |
move tlperl.straw to tlperl
git-svn-id: svn://tug.org/texlive/trunk@18210 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Master/tlpkg/tlperl/lib/encoding.pm')
-rwxr-xr-x | Master/tlpkg/tlperl/lib/encoding.pm | 669 |
1 files changed, 669 insertions, 0 deletions
diff --git a/Master/tlpkg/tlperl/lib/encoding.pm b/Master/tlpkg/tlperl/lib/encoding.pm new file mode 100755 index 00000000000..be20a494487 --- /dev/null +++ b/Master/tlpkg/tlperl/lib/encoding.pm @@ -0,0 +1,669 @@ +# $Id: encoding.pm,v 2.8 2009/02/15 17:44:13 dankogai Exp $ +package encoding; +our $VERSION = '2.6_01'; + +use Encode; +use strict; +use warnings; + +sub DEBUG () { 0 } + +BEGIN { + if ( ord("A") == 193 ) { + require Carp; + Carp::croak("encoding: pragma does not support EBCDIC platforms"); + } +} + +our $HAS_PERLIO = 0; +eval { require PerlIO::encoding }; +unless ($@) { + $HAS_PERLIO = ( PerlIO::encoding->VERSION >= 0.02 ); +} + +sub _exception { + my $name = shift; + $] > 5.008 and return 0; # 5.8.1 or higher then no + my %utfs = map { $_ => 1 } + qw(utf8 UCS-2BE UCS-2LE UTF-16 UTF-16BE UTF-16LE + UTF-32 UTF-32BE UTF-32LE); + $utfs{$name} or return 0; # UTFs or no + require Config; + Config->import(); + our %Config; + return $Config{perl_patchlevel} ? 0 : 1 # maintperl then no +} + +sub in_locale { $^H & ( $locale::hint_bits || 0 ) } + +sub _get_locale_encoding { + my $locale_encoding; + + # I18N::Langinfo isn't available everywhere + eval { + require I18N::Langinfo; + I18N::Langinfo->import(qw(langinfo CODESET)); + $locale_encoding = langinfo( CODESET() ); + }; + + my $country_language; + + no warnings 'uninitialized'; + + if ( (not $locale_encoding) && in_locale() ) { + if ( $ENV{LC_ALL} =~ /^([^.]+)\.([^.@]+)(@.*)?$/ ) { + ( $country_language, $locale_encoding ) = ( $1, $2 ); + } + elsif ( $ENV{LANG} =~ /^([^.]+)\.([^.@]+)(@.*)?$/ ) { + ( $country_language, $locale_encoding ) = ( $1, $2 ); + } + + # LANGUAGE affects only LC_MESSAGES only on glibc + } + elsif ( not $locale_encoding ) { + if ( $ENV{LC_ALL} =~ /\butf-?8\b/i + || $ENV{LANG} =~ /\butf-?8\b/i ) + { + $locale_encoding = 'utf8'; + } + + # Could do more heuristics based on the country and language + # parts of LC_ALL and LANG (the parts before the dot (if any)), + # since we have Locale::Country and Locale::Language available. + # TODO: get a database of Language -> Encoding mappings + # (the Estonian database at http://www.eki.ee/letter/ + # would be excellent!) --jhi + } + if ( defined $locale_encoding + && lc($locale_encoding) eq 'euc' + && defined $country_language ) + { + if ( $country_language =~ /^ja_JP|japan(?:ese)?$/i ) { + $locale_encoding = 'euc-jp'; + } + elsif ( $country_language =~ /^ko_KR|korean?$/i ) { + $locale_encoding = 'euc-kr'; + } + elsif ( $country_language =~ /^zh_CN|chin(?:a|ese)$/i ) { + $locale_encoding = 'euc-cn'; + } + elsif ( $country_language =~ /^zh_TW|taiwan(?:ese)?$/i ) { + $locale_encoding = 'euc-tw'; + } + else { + require Carp; + Carp::croak( + "encoding: Locale encoding '$locale_encoding' too ambiguous" + ); + } + } + + return $locale_encoding; +} + +sub import { + my $class = shift; + my $name = shift; + if ( $name eq ':_get_locale_encoding' ) { # used by lib/open.pm + my $caller = caller(); + { + no strict 'refs'; + *{"${caller}::_get_locale_encoding"} = \&_get_locale_encoding; + } + return; + } + $name = _get_locale_encoding() if $name eq ':locale'; + my %arg = @_; + $name = $ENV{PERL_ENCODING} unless defined $name; + my $enc = find_encoding($name); + unless ( defined $enc ) { + require Carp; + Carp::croak("encoding: Unknown encoding '$name'"); + } + $name = $enc->name; # canonize + unless ( $arg{Filter} ) { + DEBUG and warn "_exception($name) = ", _exception($name); + _exception($name) or ${^ENCODING} = $enc; + $HAS_PERLIO or return 1; + } + else { + defined( ${^ENCODING} ) and undef ${^ENCODING}; + + # implicitly 'use utf8' + require utf8; # to fetch $utf8::hint_bits; + $^H |= $utf8::hint_bits; + eval { + require Filter::Util::Call; + Filter::Util::Call->import; + filter_add( + sub { + my $status = filter_read(); + if ( $status > 0 ) { + $_ = $enc->decode( $_, 1 ); + DEBUG and warn $_; + } + $status; + } + ); + }; + $@ eq '' and DEBUG and warn "Filter installed"; + } + defined ${^UNICODE} and ${^UNICODE} != 0 and return 1; + for my $h (qw(STDIN STDOUT)) { + if ( $arg{$h} ) { + unless ( defined find_encoding( $arg{$h} ) ) { + require Carp; + Carp::croak( + "encoding: Unknown encoding for $h, '$arg{$h}'"); + } + eval { binmode( $h, ":raw :encoding($arg{$h})" ) }; + } + else { + unless ( exists $arg{$h} ) { + eval { + no warnings 'uninitialized'; + binmode( $h, ":raw :encoding($name)" ); + }; + } + } + if ($@) { + require Carp; + Carp::croak($@); + } + } + return 1; # I doubt if we need it, though +} + +sub unimport { + no warnings; + undef ${^ENCODING}; + if ($HAS_PERLIO) { + binmode( STDIN, ":raw" ); + binmode( STDOUT, ":raw" ); + } + else { + binmode(STDIN); + binmode(STDOUT); + } + if ( $INC{"Filter/Util/Call.pm"} ) { + eval { filter_del() }; + } +} + +1; +__END__ + +=pod + +=head1 NAME + +encoding - allows you to write your script in non-ascii or non-utf8 + +=head1 SYNOPSIS + + use encoding "greek"; # Perl like Greek to you? + use encoding "euc-jp"; # Jperl! + + # or you can even do this if your shell supports your native encoding + + perl -Mencoding=latin2 -e'...' # Feeling centrally European? + perl -Mencoding=euc-kr -e'...' # Or Korean? + + # more control + + # A simple euc-cn => utf-8 converter + use encoding "euc-cn", STDOUT => "utf8"; while(<>){print}; + + # "no encoding;" supported (but not scoped!) + no encoding; + + # an alternate way, Filter + use encoding "euc-jp", Filter=>1; + # now you can use kanji identifiers -- in euc-jp! + + # switch on locale - + # note that this probably means that unless you have a complete control + # over the environments the application is ever going to be run, you should + # NOT use the feature of encoding pragma allowing you to write your script + # in any recognized encoding because changing locale settings will wreck + # the script; you can of course still use the other features of the pragma. + use encoding ':locale'; + +=head1 ABSTRACT + +Let's start with a bit of history: Perl 5.6.0 introduced Unicode +support. You could apply C<substr()> and regexes even to complex CJK +characters -- so long as the script was written in UTF-8. But back +then, text editors that supported UTF-8 were still rare and many users +instead chose to write scripts in legacy encodings, giving up a whole +new feature of Perl 5.6. + +Rewind to the future: starting from perl 5.8.0 with the B<encoding> +pragma, you can write your script in any encoding you like (so long +as the C<Encode> module supports it) and still enjoy Unicode support. +This pragma achieves that by doing the following: + +=over + +=item * + +Internally converts all literals (C<q//,qq//,qr//,qw///, qx//>) from +the encoding specified to utf8. In Perl 5.8.1 and later, literals in +C<tr///> and C<DATA> pseudo-filehandle are also converted. + +=item * + +Changing PerlIO layers of C<STDIN> and C<STDOUT> to the encoding + specified. + +=back + +=head2 Literal Conversions + +You can write code in EUC-JP as follows: + + my $Rakuda = "\xF1\xD1\xF1\xCC"; # Camel in Kanji + #<-char-><-char-> # 4 octets + s/\bCamel\b/$Rakuda/; + +And with C<use encoding "euc-jp"> in effect, it is the same thing as +the code in UTF-8: + + my $Rakuda = "\x{99F1}\x{99DD}"; # two Unicode Characters + s/\bCamel\b/$Rakuda/; + +=head2 PerlIO layers for C<STD(IN|OUT)> + +The B<encoding> pragma also modifies the filehandle layers of +STDIN and STDOUT to the specified encoding. Therefore, + + use encoding "euc-jp"; + my $message = "Camel is the symbol of perl.\n"; + my $Rakuda = "\xF1\xD1\xF1\xCC"; # Camel in Kanji + $message =~ s/\bCamel\b/$Rakuda/; + print $message; + +Will print "\xF1\xD1\xF1\xCC is the symbol of perl.\n", +not "\x{99F1}\x{99DD} is the symbol of perl.\n". + +You can override this by giving extra arguments; see below. + +=head2 Implicit upgrading for byte strings + +By default, if strings operating under byte semantics and strings +with Unicode character data are concatenated, the new string will +be created by decoding the byte strings as I<ISO 8859-1 (Latin-1)>. + +The B<encoding> pragma changes this to use the specified encoding +instead. For example: + + use encoding 'utf8'; + my $string = chr(20000); # a Unicode string + utf8::encode($string); # now it's a UTF-8 encoded byte string + # concatenate with another Unicode string + print length($string . chr(20000)); + +Will print C<2>, because C<$string> is upgraded as UTF-8. Without +C<use encoding 'utf8';>, it will print C<4> instead, since C<$string> +is three octets when interpreted as Latin-1. + +=head2 Side effects + +If the C<encoding> pragma is in scope then the lengths returned are +calculated from the length of C<$/> in Unicode characters, which is not +always the same as the length of C<$/> in the native encoding. + +This pragma affects utf8::upgrade, but not utf8::downgrade. + +=head1 FEATURES THAT REQUIRE 5.8.1 + +Some of the features offered by this pragma requires perl 5.8.1. Most +of these are done by Inaba Hiroto. Any other features and changes +are good for 5.8.0. + +=over + +=item "NON-EUC" doublebyte encodings + +Because perl needs to parse script before applying this pragma, such +encodings as Shift_JIS and Big-5 that may contain '\' (BACKSLASH; +\x5c) in the second byte fails because the second byte may +accidentally escape the quoting character that follows. Perl 5.8.1 +or later fixes this problem. + +=item tr// + +C<tr//> was overlooked by Perl 5 porters when they released perl 5.8.0 +See the section below for details. + +=item DATA pseudo-filehandle + +Another feature that was overlooked was C<DATA>. + +=back + +=head1 USAGE + +=over 4 + +=item use encoding [I<ENCNAME>] ; + +Sets the script encoding to I<ENCNAME>. And unless ${^UNICODE} +exists and non-zero, PerlIO layers of STDIN and STDOUT are set to +":encoding(I<ENCNAME>)". + +Note that STDERR WILL NOT be changed. + +Also note that non-STD file handles remain unaffected. Use C<use +open> or C<binmode> to change layers of those. + +If no encoding is specified, the environment variable L<PERL_ENCODING> +is consulted. If no encoding can be found, the error C<Unknown encoding +'I<ENCNAME>'> will be thrown. + +=item use encoding I<ENCNAME> [ STDIN =E<gt> I<ENCNAME_IN> ...] ; + +You can also individually set encodings of STDIN and STDOUT via the +C<< STDIN => I<ENCNAME> >> form. In this case, you cannot omit the +first I<ENCNAME>. C<< STDIN => undef >> turns the IO transcoding +completely off. + +When ${^UNICODE} exists and non-zero, these options will completely +ignored. ${^UNICODE} is a variable introduced in perl 5.8.1. See +L<perlrun> see L<perlvar/"${^UNICODE}"> and L<perlrun/"-C"> for +details (perl 5.8.1 and later). + +=item use encoding I<ENCNAME> Filter=E<gt>1; + +This turns the encoding pragma into a source filter. While the +default approach just decodes interpolated literals (in qq() and +qr()), this will apply a source filter to the entire source code. See +L</"The Filter Option"> below for details. + +=item no encoding; + +Unsets the script encoding. The layers of STDIN, STDOUT are +reset to ":raw" (the default unprocessed raw stream of bytes). + +=back + +=head1 The Filter Option + +The magic of C<use encoding> is not applied to the names of +identifiers. In order to make C<${"\x{4eba}"}++> ($human++, where human +is a single Han ideograph) work, you still need to write your script +in UTF-8 -- or use a source filter. That's what 'Filter=>1' does. + +What does this mean? Your source code behaves as if it is written in +UTF-8 with 'use utf8' in effect. So even if your editor only supports +Shift_JIS, for example, you can still try examples in Chapter 15 of +C<Programming Perl, 3rd Ed.>. For instance, you can use UTF-8 +identifiers. + +This option is significantly slower and (as of this writing) non-ASCII +identifiers are not very stable WITHOUT this option and with the +source code written in UTF-8. + +=head2 Filter-related changes at Encode version 1.87 + +=over + +=item * + +The Filter option now sets STDIN and STDOUT like non-filter options. +And C<< STDIN=>I<ENCODING> >> and C<< STDOUT=>I<ENCODING> >> work like +non-filter version. + +=item * + +C<use utf8> is implicitly declared so you no longer have to C<use +utf8> to C<${"\x{4eba}"}++>. + +=back + +=head1 CAVEATS + +=head2 NOT SCOPED + +The pragma is a per script, not a per block lexical. Only the last +C<use encoding> or C<no encoding> matters, and it affects +B<the whole script>. However, the <no encoding> pragma is supported and +B<use encoding> can appear as many times as you want in a given script. +The multiple use of this pragma is discouraged. + +By the same reason, the use this pragma inside modules is also +discouraged (though not as strongly discouraged as the case above. +See below). + +If you still have to write a module with this pragma, be very careful +of the load order. See the codes below; + + # called module + package Module_IN_BAR; + use encoding "bar"; + # stuff in "bar" encoding here + 1; + + # caller script + use encoding "foo" + use Module_IN_BAR; + # surprise! use encoding "bar" is in effect. + +The best way to avoid this oddity is to use this pragma RIGHT AFTER +other modules are loaded. i.e. + + use Module_IN_BAR; + use encoding "foo"; + +=head2 DO NOT MIX MULTIPLE ENCODINGS + +Notice that only literals (string or regular expression) having only +legacy code points are affected: if you mix data like this + + \xDF\x{100} + +the data is assumed to be in (Latin 1 and) Unicode, not in your native +encoding. In other words, this will match in "greek": + + "\xDF" =~ /\x{3af}/ + +but this will not + + "\xDF\x{100}" =~ /\x{3af}\x{100}/ + +since the C<\xDF> (ISO 8859-7 GREEK SMALL LETTER IOTA WITH TONOS) on +the left will B<not> be upgraded to C<\x{3af}> (Unicode GREEK SMALL +LETTER IOTA WITH TONOS) because of the C<\x{100}> on the left. You +should not be mixing your legacy data and Unicode in the same string. + +This pragma also affects encoding of the 0x80..0xFF code point range: +normally characters in that range are left as eight-bit bytes (unless +they are combined with characters with code points 0x100 or larger, +in which case all characters need to become UTF-8 encoded), but if +the C<encoding> pragma is present, even the 0x80..0xFF range always +gets UTF-8 encoded. + +After all, the best thing about this pragma is that you don't have to +resort to \x{....} just to spell your name in a native encoding. +So feel free to put your strings in your encoding in quotes and +regexes. + +=head2 tr/// with ranges + +The B<encoding> pragma works by decoding string literals in +C<q//,qq//,qr//,qw///, qx//> and so forth. In perl 5.8.0, this +does not apply to C<tr///>. Therefore, + + use encoding 'euc-jp'; + #.... + $kana =~ tr/\xA4\xA1-\xA4\xF3/\xA5\xA1-\xA5\xF3/; + # -------- -------- -------- -------- + +Does not work as + + $kana =~ tr/\x{3041}-\x{3093}/\x{30a1}-\x{30f3}/; + +=over + +=item Legend of characters above + + utf8 euc-jp charnames::viacode() + ----------------------------------------- + \x{3041} \xA4\xA1 HIRAGANA LETTER SMALL A + \x{3093} \xA4\xF3 HIRAGANA LETTER N + \x{30a1} \xA5\xA1 KATAKANA LETTER SMALL A + \x{30f3} \xA5\xF3 KATAKANA LETTER N + +=back + +This counterintuitive behavior has been fixed in perl 5.8.1. + +=head3 workaround to tr///; + +In perl 5.8.0, you can work around as follows; + + use encoding 'euc-jp'; + # .... + eval qq{ \$kana =~ tr/\xA4\xA1-\xA4\xF3/\xA5\xA1-\xA5\xF3/ }; + +Note the C<tr//> expression is surrounded by C<qq{}>. The idea behind +is the same as classic idiom that makes C<tr///> 'interpolate'. + + tr/$from/$to/; # wrong! + eval qq{ tr/$from/$to/ }; # workaround. + +Nevertheless, in case of B<encoding> pragma even C<q//> is affected so +C<tr///> not being decoded was obviously against the will of Perl5 +Porters so it has been fixed in Perl 5.8.1 or later. + +=head1 EXAMPLE - Greekperl + + use encoding "iso 8859-7"; + + # \xDF in ISO 8859-7 (Greek) is \x{3af} in Unicode. + + $a = "\xDF"; + $b = "\x{100}"; + + printf "%#x\n", ord($a); # will print 0x3af, not 0xdf + + $c = $a . $b; + + # $c will be "\x{3af}\x{100}", not "\x{df}\x{100}". + + # chr() is affected, and ... + + print "mega\n" if ord(chr(0xdf)) == 0x3af; + + # ... ord() is affected by the encoding pragma ... + + print "tera\n" if ord(pack("C", 0xdf)) == 0x3af; + + # ... as are eq and cmp ... + + print "peta\n" if "\x{3af}" eq pack("C", 0xdf); + print "exa\n" if "\x{3af}" cmp pack("C", 0xdf) == 0; + + # ... but pack/unpack C are not affected, in case you still + # want to go back to your native encoding + + print "zetta\n" if unpack("C", (pack("C", 0xdf))) == 0xdf; + +=head1 KNOWN PROBLEMS + +=over + +=item literals in regex that are longer than 127 bytes + +For native multibyte encodings (either fixed or variable length), +the current implementation of the regular expressions may introduce +recoding errors for regular expression literals longer than 127 bytes. + +=item EBCDIC + +The encoding pragma is not supported on EBCDIC platforms. +(Porters who are willing and able to remove this limitation are +welcome.) + +=item format + +This pragma doesn't work well with format because PerlIO does not +get along very well with it. When format contains non-ascii +characters it prints funny or gets "wide character warnings". +To understand it, try the code below. + + # Save this one in utf8 + # replace *non-ascii* with a non-ascii string + my $camel; + format STDOUT = + *non-ascii*@>>>>>>> + $camel + . + $camel = "*non-ascii*"; + binmode(STDOUT=>':encoding(utf8)'); # bang! + write; # funny + print $camel, "\n"; # fine + +Without binmode this happens to work but without binmode, print() +fails instead of write(). + +At any rate, the very use of format is questionable when it comes to +unicode characters since you have to consider such things as character +width (i.e. double-width for ideographs) and directions (i.e. BIDI for +Arabic and Hebrew). + +=item Thread safety + +C<use encoding ...> is not thread-safe (i.e., do not use in threaded +applications). + +=back + +=head2 The Logic of :locale + +The logic of C<:locale> is as follows: + +=over 4 + +=item 1. + +If the platform supports the langinfo(CODESET) interface, the codeset +returned is used as the default encoding for the open pragma. + +=item 2. + +If 1. didn't work but we are under the locale pragma, the environment +variables LC_ALL and LANG (in that order) are matched for encodings +(the part after C<.>, if any), and if any found, that is used +as the default encoding for the open pragma. + +=item 3. + +If 1. and 2. didn't work, the environment variables LC_ALL and LANG +(in that order) are matched for anything looking like UTF-8, and if +any found, C<:utf8> is used as the default encoding for the open +pragma. + +=back + +If your locale environment variables (LC_ALL, LC_CTYPE, LANG) +contain the strings 'UTF-8' or 'UTF8' (case-insensitive matching), +the default encoding of your STDIN, STDOUT, and STDERR, and of +B<any subsequent file open>, is UTF-8. + +=head1 HISTORY + +This pragma first appeared in Perl 5.8.0. For features that require +5.8.1 and better, see above. + +The C<:locale> subpragma was implemented in 2.01, or Perl 5.8.6. + +=head1 SEE ALSO + +L<perlunicode>, L<Encode>, L<open>, L<Filter::Util::Call>, + +Ch. 15 of C<Programming Perl (3rd Edition)> +by Larry Wall, Tom Christiansen, Jon Orwant; +O'Reilly & Associates; ISBN 0-596-00027-8 + +=cut |