package open;
+use warnings;
use Carp;
$open::hint_bits = 0x20000;
-use vars qw(%layers @layers);
+our $VERSION = '1.01';
-# Populate hash in non-PerlIO case
-%layers = (crlf => 1, raw => 0) unless (@layers);
+my $locale_encoding;
-# warn join(',',keys %layers);
+sub in_locale { $^H & ($locale::hint_bits || 0)}
-our $VERSION = '1.00';
+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'));
- my @in = split(/\s+/,$in);
- my @out = split(/\s+/,$out);
+ my ($in,$out) = split(/\0/,(${^OPEN} || "\0"), -1);
while (@args) {
my $type = shift(@args);
- my $discp = 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 $layer (split(/\s+/,$discp)) {
+ foreach my $layer (split(/\s+/,$dscp)) {
$layer =~ s/^://;
- unless(exists $layers{$layer}) {
- carp("Unknown discipline layer '$layer'");
+ if ($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 ($layer =~ /^(crlf|raw)$/) {
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);
+ ${^OPEN} = join("\0",$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;
=head1 SYNOPSIS
- use open IN => ":crlf", OUT => ":raw";
+ 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
-The open pragma is used to declare one or more default disciplines for
-I/O operations. Any open() and readpipe() (aka qx//) operators found
-within the lexical scope of this pragma will use the declared defaults.
-Neither open() with an explicit set of disciplines, nor sysopen() are
-influenced by this pragma.
+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<open> pragma serves as one of the interfaces to declare default
+"layers" (aka disciplines) for all I/O.
+
+The C<open> 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<IN> subpragma you can declare the default layers
+of input streams, and with the C<OUT> subpragma you can declare
+the default layers of output streams. With the C<IO> 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:
-Only the two pseudo-disciplines ":raw" and ":crlf" are currently
-available.
+ $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, "<koi8");
+ printf "%#x\n", ord(<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<koi8r>. 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<any subsequent file open>, 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 currently
-no-ops on platforms where binmode() is a no-op, but will be
-supported everywhere in future.
-
-=head1 UNIMPLEMENTED FUNCTIONALITY
-
-Full-fledged support for I/O disciplines is currently unimplemented.
-When they are eventually supported, this pragma will serve as one of
-the interfaces to declare default disciplines for all I/O.
+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.
-In future, any default disciplines declared by this pragma will be
-available by the special discipline name ":DEFAULT", and could be used
-within handle constructors that allow disciplines to be specified.
-This would make it possible to stack new disciplines over the default
-ones.
+=head1 IMPLEMENTATION DETAILS
- open FH, "<:para :DEFAULT", $file or die "can't open $file: $!";
+There is a class method in C<PerlIO::Layer> C<find> which is
+implemented as XS code. It is called by C<import> to validate the
+layers:
-Socket and directory handles will also support disciplines in
-future.
+ PerlIO::Layer::->find("perlio")
-Full support for I/O disciplines will enable all of the supported
-disciplines to work on all platforms.
+The return value (if defined) is a Perl object, of class
+C<PerlIO::Layer> which is created by the C code in F<perlio.c>. As
+yet there is nothing useful you can do with the object at the perl
+level.
=head1 SEE ALSO
-L<perlfunc/"binmode">, L<perlfunc/"open">, L<perlunicode>
+L<perlfunc/"binmode">, L<perlfunc/"open">, L<perlunicode>, L<PerlIO>,
+L<encoding>
=cut
https://perl5.git.perl.org / perl5.git / blobdiff