package open;
use warnings;
-use Carp;
-$open::hint_bits = 0x20000;
+$open::hint_bits = 0x20000; # HINT_LOCALIZE_HH
-our $VERSION = '1.01';
+our $VERSION = '1.04_01';
+
+require 5.008001; # for PerlIO::get_layers()
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 _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;
+ croak("open: needs explicit list of PerlIO layers") unless @args;
my $std;
$^H |= $open::hint_bits;
my ($in,$out) = split(/\0/,(${^OPEN} || "\0"), -1);
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;
(warnings::warnif("layer", "Cannot figure out an encoding to use"), last)
unless defined $locale_encoding;
my $target = $layer; # the layer name itself
$target =~ s/^(\w+)\(.+\)$/$1/; # strip parameters
- unless(PerlIO::Layer::->find($target)) {
- warnings::warnif("layer", "Unknown discipline layer '$layer'");
+ unless(PerlIO::Layer::->find($target,1)) {
+ warnings::warnif("layer", "Unknown PerlIO layer '$target'");
}
}
push(@val,":$layer");
}
}
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 $in or $out;
+ ${^OPEN} = join("\0", $in, $out);
if ($std) {
if ($in) {
if ($in =~ /:utf8\b/) {
=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)";
=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.
+Three-argument opens are not affected by this pragma since there you
+(can) explicitly specify the layers and are supposed to know what you
+are doing.
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:
many encodings have several aliases. See L<Encode::Supported> for
details and the list of supported locales.
-Note that C<:utf8> discipline must always be specified exactly like
+Note that C<:utf8> PerlIO layer must always be specified exactly like
that, it is not subject to the loose matching of encoding names.
When open() is given an explicit list of layers they are appended to
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.
+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.
projects / p5sagit/p5-mst-13.2.git / blobdiff