package open;
-use Carp;
-$open::hint_bits = 0x20000;
+use warnings;
-our $VERSION = '1.01';
+our $VERSION = '1.05';
+
+require 5.008001; # for PerlIO::get_layers()
my $locale_encoding;
-sub in_locale { $^H & $locale::hint_bits }
-
-sub _get_locale_encoding {
- unless (defined $locale_encoding) {
- # I18N::Langinfo isn't available everywhere
- eval {
- require I18N::Langinfo;
- I18N::Langinfo->import(qw(langinfo CODESET));
- $locale_encoding = langinfo(CODESET());
- };
- unless ($@) {
- print "# locale_encoding = $locale_encoding\n";
- }
- my $country_language;
- 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_TW|taiwan(?:ese)?$/i) {
- $locale_encoding = 'euc-tw';
- }
- croak "Locale encoding 'euc' too ambiguous"
- if $locale_encoding eq 'euc';
- }
+sub _get_encname {
+ return ($1, Encode::resolve_alias($1)) if $_[0] =~ /^:?encoding\((.+)\)$/;
+ return;
+}
+
+sub croak {
+ require Carp; goto &Carp::croak;
+}
+
+sub _drop_oldenc {
+ # If by the time we arrive here there already is at the top of the
+ # perlio layer stack an encoding identical to what we would like
+ # to push via this open pragma, we will pop away the old encoding
+ # (+utf8) so that we can push ourselves in place (this is easier
+ # than ignoring pushing ourselves because of the way how ${^OPEN}
+ # works). So we are looking for something like
+ #
+ # stdio encoding(xxx) utf8
+ #
+ # in the existing layer stack, and in the new stack chunk for
+ #
+ # :encoding(xxx)
+ #
+ # If we find a match, we pop the old stack (once, since
+ # the utf8 is just a flag on the encoding layer)
+ my ($h, @new) = @_;
+ return unless @new >= 1 && $new[-1] =~ /^:encoding\(.+\)$/;
+ my @old = PerlIO::get_layers($h);
+ return unless @old >= 3 &&
+ $old[-1] eq 'utf8' &&
+ $old[-2] =~ /^encoding\(.+\)$/;
+ require Encode;
+ my ($loname, $lcname) = _get_encname($old[-2]);
+ unless (defined $lcname) { # Should we trust get_layers()?
+ croak("open: Unknown encoding '$loname'");
+ }
+ my ($voname, $vcname) = _get_encname($new[-1]);
+ unless (defined $vcname) {
+ croak("open: Unknown encoding '$voname'");
+ }
+ if ($lcname eq $vcname) {
+ binmode($h, ":pop"); # utf8 is part of the encoding layer
}
}
sub import {
my ($class,@args) = @_;
- croak("`use open' needs explicit list of disciplines") unless @args;
- $^H |= $open::hint_bits;
+ croak("open: needs explicit list of PerlIO layers") unless @args;
+ my $std;
my ($in,$out) = split(/\0/,(${^OPEN} || "\0"), -1);
while (@args) {
my $type = shift(@args);
if ($type =~ /^:?(utf8|locale|encoding\(.+\))$/) {
$type = 'IO';
$dscp = ":$1";
+ } elsif ($type eq ':std') {
+ $std = 1;
+ next;
} else {
$dscp = shift(@args) || '';
}
foreach my $layer (split(/\s+/,$dscp)) {
$layer =~ s/^://;
if ($layer eq 'locale') {
- use Encode;
- _get_locale_encoding()
+ require Encode;
+ require encoding;
+ $locale_encoding = encoding::_get_locale_encoding()
unless defined $locale_encoding;
- croak "Cannot figure out an encoding to use"
+ (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)";
- }
+ $layer = "encoding($locale_encoding)";
+ $std = 1;
} else {
- unless(PerlIO::Layer::->find($layer)) {
- carp("Unknown discipline layer '$layer'");
+ my $target = $layer; # the layer name itself
+ $target =~ s/^(\w+)\(.+\)$/$1/; # strip parameters
+
+ unless(PerlIO::Layer::->find($target,1)) {
+ warnings::warnif("layer", "Unknown PerlIO layer '$target'");
}
}
push(@val,":$layer");
$^H{"open_$type"} = $layer;
}
}
- # print "# type = $type, val = @val\n";
if ($type eq 'IN') {
- $in = join(' ',@val);
+ _drop_oldenc(*STDIN, @val);
+ $in = join(' ', @val);
}
elsif ($type eq 'OUT') {
- $out = join(' ',@val);
+ _drop_oldenc(*STDOUT, @val);
+ $out = join(' ', @val);
}
elsif ($type eq 'IO') {
- $in = $out = join(' ',@val);
+ _drop_oldenc(*STDIN, @val);
+ _drop_oldenc(*STDOUT, @val);
+ $in = $out = join(' ', @val);
}
else {
- croak "Unknown discipline class '$type'";
+ croak "Unknown PerlIO layer class '$type'";
+ }
+ }
+ ${^OPEN} = join("\0", $in, $out);
+ if ($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");
+ }
}
}
- ${^OPEN} = join("\0",$in,$out);
}
1;
=head1 NAME
-open - perl pragma to set default disciplines for input and output
+open - perl pragma to set default PerlIO layers for input and output
=head1 SYNOPSIS
- use open IN => ":crlf", OUT => ":raw";
+ use open IN => ":crlf", OUT => ":bytes";
use open OUT => ':utf8';
use open IO => ":encoding(iso-8859-7)";
use open IO => ':locale';
- use open ':utf8';
+ use open ':encoding(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
+Full-fledged support for I/O layers 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.
+"layers" (also known as "disciplines") for all I/O. Any two-argument
+open(), readpipe() (aka qx//) and similar operators found within the
+lexical scope of this pragma will use the declared defaults.
+Even three-argument opens may be affected by this pragma
+when they don't specify IO layers in MODE.
With the C<IN> subpragma you can declare the default layers
of input streams, and with the C<OUT> subpragma you can declare
If you have a legacy encoding, you can use the C<:encoding(...)> tag.
-if you want to set your encoding disciplines based on your
+If you want to set your encoding layers based on your
locale environment variables, you can use the C<:locale> tag.
For example:
These are equivalent
- use open ':utf8';
- use open IO => ':utf8';
+ use open ':encoding(utf8)';
+ use open IO => ':encoding(utf8)';
as are 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 matching of encoding names is loose: case does not matter, and
+many encodings have several aliases. See L<Encode::Supported> for
+details and the list of supported locales.
+
+When open() is given an explicit list of layers (with the three-arg
+syntax), they override 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<:encoding(utf8)>, a C<:std> will mean that STDIN, STDOUT,
+and STDERR are also in C<:encoding(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 described in full in L<encoding>,
+but in short it is first trying nl_langinfo(CODESET) and then
+guessing from the LC_ALL and LANG locale environment variables.
-Directory handles may also support disciplines in future.
+Directory handles may also support PerlIO layers in the 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.
+pseudo-layers C<:bytes> and C<:crlf> are available.
-The ":raw" discipline corresponds to "binary mode" and the ":crlf"
-discipline corresponds to "text mode" on platforms that distinguish
+The C<:bytes> layer corresponds to "binary mode" and the C<:crlf>
+layer 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, including Windows). These two layers are no-ops on
platforms where binmode() is a no-op, but perform their functions
everywhere if PerlIO is enabled.
https://perl5.git.perl.org / perl5.git / blobdiff