package open; use warnings; use Carp; $open::hint_bits = 0x20000; our $VERSION = '1.01'; my $locale_encoding; sub in_locale { $^H & ($locale::hint_bits || 0)} sub _get_locale_encoding { unless (defined $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); } } 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 && $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'; } croak "Locale encoding 'euc' too ambiguous" if $locale_encoding eq 'euc'; } } } sub import { my ($class,@args) = @_; croak("`use open' needs explicit list of disciplines") unless @args; my $std; $^H |= $open::hint_bits; my ($in,$out) = split(/\0/,(${^OPEN} || "\0"), -1); while (@args) { my $type = shift(@args); my $dscp; if ($type =~ /^:?(utf8|locale|encoding\(.+\))$/) { $type = 'IO'; $dscp = ":$1"; } elsif ($type eq ':std') { $std = 1; next; } else { $dscp = shift(@args) || ''; } my @val; foreach my $layer (split(/\s+/,$dscp)) { $layer =~ s/^://; if ($layer eq 'locale') { use Encode; _get_locale_encoding() unless defined $locale_encoding; (warnings::warnif("layer", "Cannot figure out an encoding to use"), last) unless defined $locale_encoding; if ($locale_encoding =~ /^utf-?8$/i) { $layer = "utf8"; } else { $layer = "encoding($locale_encoding)"; } $std = 1; } else { my $target = $layer; # the layer name itself $target =~ s/^(\w+)\(.+\)$/$1/; # strip parameters unless(PerlIO::Layer::->find($target)) { warnings::warnif("layer", "Unknown discipline layer '$layer'"); } } push(@val,":$layer"); if ($layer =~ /^(crlf|raw)$/) { $^H{"open_$type"} = $layer; } } if ($type eq 'IN') { $in = join(' ',@val); } elsif ($type eq 'OUT') { $out = join(' ',@val); } elsif ($type eq 'IO') { $in = $out = join(' ',@val); } else { croak "Unknown discipline class '$type'"; } } ${^OPEN} = join("\0",$in,$out) if $in or $out; if ($std) { if ($in) { if ($in =~ /:utf8\b/) { binmode(STDIN, ":utf8"); } elsif ($in =~ /(\w+\(.+\))/) { binmode(STDIN, ":$1"); } } if ($out) { if ($out =~ /:utf8\b/) { binmode(STDOUT, ":utf8"); binmode(STDERR, ":utf8"); } elsif ($out =~ /(\w+\(.+\))/) { binmode(STDOUT, ":$1"); binmode(STDERR, ":$1"); } } } } 1; __END__ =head1 NAME open - perl pragma to set default disciplines for input and output =head1 SYNOPSIS use open IN => ":crlf", OUT => ":raw"; use open OUT => ':utf8'; use open IO => ":encoding(iso-8859-7)"; use open IO => ':locale'; use open ':utf8'; use open ':locale'; use open ':encoding(iso-8859-7)'; use open ':std'; =head1 DESCRIPTION Full-fledged support for I/O disciplines is now implemented provided Perl is configured to use PerlIO as its IO system (which is now the default). The C pragma serves as one of the interfaces to declare default "layers" (aka disciplines) for all I/O. The C pragma is used to declare one or more default layers for I/O operations. Any open(), readpipe() (aka qx//) and similar operators found within the lexical scope of this pragma will use the declared defaults. With the C subpragma you can declare the default layers of input streams, and with the C subpragma you can declare the default layers of output streams. With the C subpragma you can control both input and output streams simultaneously. If you have a legacy encoding, you can use the C<:encoding(...)> tag. if you want to set your encoding disciplines based on your locale environment variables, you can use the C<:locale> tag. For example: $ENV{LANG} = 'ru_RU.KOI8-R'; # the :locale will probe the locale environment variables like LANG use open OUT => ':locale'; open(O, ">koi8"); print O chr(0x430); # Unicode CYRILLIC SMALL LETTER A = KOI8-R 0xc1 close O; open(I, "), "\n"; # this should print 0xc1 close I; These are equivalent use open ':utf8'; use open IO => ':utf8'; as are these use open ':locale'; use open IO => ':locale'; and these use open ':encoding(iso-8859-7)'; use open IO => ':encoding(iso-8859-7)'; When open() is given an explicit list of layers they are appended to the list declared using this pragma. The C<:std> subpragma on its own has no effect, but if combined with the C<:utf8> or C<:encoding> subpragmas, it converts the standard filehandles (STDIN, STDOUT, STDERR) to comply with encoding selected for input/output handles. For example, if both input and out are chosen to be C<:utf8>, a C<:std> will mean that STDIN, STDOUT, and STDERR are also in C<:utf8>. On the other hand, if only output is chosen to be in C<< :encoding(koi8r) >>, a C<:std> will cause only the STDOUT and STDERR to be in C. The C<:locale> subpragma implicitly turns on C<:std>. 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 (LANGUAGE, 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, is UTF-8. Directory handles may also support disciplines in future. =head1 NONPERLIO FUNCTIONALITY If Perl is not built to use PerlIO as its IO system then only the two pseudo-disciplines ":raw" and ":crlf" are available. The ":raw" discipline corresponds to "binary mode" and the ":crlf" discipline corresponds to "text mode" on platforms that distinguish between the two modes when opening files (which is many DOS-like platforms, including Windows). These two disciplines are no-ops on platforms where binmode() is a no-op, but perform their functions everywhere if PerlIO is enabled. =head1 IMPLEMENTATION DETAILS There is a class method in C C which is implemented as XS code. It is called by C to validate the layers: PerlIO::Layer::->find("perlio") The return value (if defined) is a Perl object, of class C which is created by the C code in F. As yet there is nothing useful you can do with the object at the perl level. =head1 SEE ALSO L, L, L, L, L =cut