FM / perl5

/usr/share/perl5

Name	Size	Mode	Actions
Attribute/	-	0755	rm
B/	-	0755	rm
Class/	-	0755	rm
Compress/	-	0755	rm
Config/	-	0755	rm
CPAN/	-	0755	rm
DBM_Filter/	-	0755	rm
Devel/	-	0755	rm
encoding/	-	0755	rm
ExtUtils/	-	0755	rm
File/	-	0755	rm
Getopt/	-	0755	rm
I18N/	-	0755	rm
IO/	-	0755	rm
IPC/	-	0755	rm
Locale/	-	0755	rm
Math/	-	0755	rm
Memoize/	-	0755	rm
Module/	-	0755	rm
Net/	-	0755	rm
overload/	-	0755	rm
Pod/	-	0755	rm
pod/	-	0755	rm
Search/	-	0755	rm
Term/	-	0755	rm
Text/	-	0755	rm
Thread/	-	0755	rm
Tie/	-	0755	rm
Time/	-	0755	rm
Unicode/	-	0755	rm
unicore/	-	0755	rm
URI/	-	0755	rm
User/	-	0755	rm
vendor_perl/	-	0755	rm
warnings/	-	0755	rm
AnyDBM_File.pm	2618	0644	edit dl rm
AutoLoader.pm	15797	0644	edit dl rm
AutoSplit.pm	19637	0644	edit dl rm
autouse.pm	4238	0644	edit dl rm
base.pm	10980	0644	edit dl rm
Benchmark.pm	31025	0644	edit dl rm
blib.pm	2086	0644	edit dl rm
bytes.pm	3754	0644	edit dl rm
bytes_heavy.pl	758	0644	edit dl rm
charnames.pm	20867	0644	edit dl rm
CORE.pod	3188	0644	edit dl rm
DB.pm	18922	0644	edit dl rm
DBM_Filter.pm	14385	0644	edit dl rm
deprecate.pm	3079	0644	edit dl rm
diagnostics.pm	19038	0644	edit dl rm
DirHandle.pm	1556	0644	edit dl rm
Dumpvalue.pm	17556	0644	edit dl rm
dumpvar.pl	15555	0644	edit dl rm
English.pm	4761	0644	edit dl rm
feature.pm	17085	0644	edit dl rm
fields.pm	9489	0644	edit dl rm
FileCache.pm	5572	0644	edit dl rm
FileHandle.pm	6784	0644	edit dl rm
filetest.pm	4003	0644	edit dl rm
FindBin.pm	4561	0644	edit dl rm
if.pm	3340	0644	edit dl rm
integer.pm	3254	0644	edit dl rm
Internals.pod	2576	0644	edit dl rm
less.pm	3204	0644	edit dl rm
locale.pm	4855	0644	edit dl rm
Memoize.pm	36192	0644	edit dl rm
meta_notation.pm	2117	0644	edit dl rm
NEXT.pm	18846	0644	edit dl rm
open.pm	8021	0644	edit dl rm
overload.pm	53314	0644	edit dl rm
overloading.pm	1808	0644	edit dl rm
perl5db.pl	316420	0644	edit dl rm
PerlIO.pm	10459	0644	edit dl rm
Safe.pm	25082	0644	edit dl rm
SelectSaver.pm	1076	0644	edit dl rm
SelfLoader.pm	17692	0644	edit dl rm
sigtrap.pm	7606	0644	edit dl rm
sort.pm	6081	0644	edit dl rm
strict.pm	4738	0644	edit dl rm
subs.pm	848	0644	edit dl rm
Symbol.pm	4799	0644	edit dl rm
Test.pm	30057	0644	edit dl rm
Thread.pm	8287	0644	edit dl rm
UNIVERSAL.pm	6594	0644	edit dl rm
URI.pm	34790	0644	edit dl rm
utf8.pm	9116	0644	edit dl rm
utf8_heavy.pl	31615	0644	edit dl rm
vars.pm	2414	0644	edit dl rm
vmsish.pm	4313	0644	edit dl rm
warnings.pm	44756	0644	edit dl rm
XSLoader.pm	11267	0644	edit dl rm
_charnames.pm	33166	0644	edit dl rm

Edit: /usr/share/perl5/open.pm (8021B)

package open;
use warnings;

our $VERSION = '1.11';

require 5.008001; # for PerlIO::get_layers()

my $locale_encoding;

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("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);
	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') {
		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;
                $layer = "encoding($locale_encoding)";
		$std = 1;
	    } else {
		my $target = $layer;		# the layer name itself
		$target =~ s/^(\w+)$.+$$/$1/;	# strip parameters

unless(PerlIO::Layer::->find($target,1)) {
		    warnings::warnif("layer", "Unknown PerlIO layer '$target'");
		}
	    }
	    push(@val,":$layer");
	    if ($layer =~ /^(crlf|raw)$/) {
		$^H{"open_$type"} = $layer;
	    }
	}
	if ($type eq 'IN') {
	    _drop_oldenc(*STDIN, @val) if $std;
	    $in  = join(' ', @val);
	}
	elsif ($type eq 'OUT') {
	    if ($std) {
		_drop_oldenc(*STDOUT, @val);
		_drop_oldenc(*STDERR, @val);
	    }
	    $out = join(' ', @val);
	}
	elsif ($type eq 'IO') {
	    if ($std) {
		_drop_oldenc(*STDIN, @val);
		_drop_oldenc(*STDOUT, @val);
		_drop_oldenc(*STDERR, @val);
	    }
	    $in = $out = join(' ', @val);
	}
	else {
	    croak "Unknown PerlIO layer class '$type' (need IN, OUT or IO)";
	}
    }
    ${^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");
	    }
	}
    }
}

1;
__END__

=head1 NAME

open - perl pragma to set default PerlIO layers for input and output

=head1 SYNOPSIS

use open IN  => ":crlf", OUT => ":bytes";
    use open OUT => ':utf8';
    use open IO  => ":encoding(iso-8859-7)";

use open IO  => ':locale';

use open ':encoding(UTF-8)';
    use open ':locale';
    use open ':encoding(iso-8859-7)';

use open ':std';

=head1 DESCRIPTION

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" (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
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 layers 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, "<koi8");
    printf "%#x\n", ord(<I>), "\n"; # this should print 0xc1
    close I;

These are equivalent

use open ':encoding(UTF-8)';
    use open IO => ':encoding(UTF-8)';

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)';

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.  open() can
also be given a single colon (:) for a layer name, to override this pragma
and use the default (C<:raw> on Unix, C<:crlf> on Windows).

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(UTF-8)>, a C<:std> will mean that STDIN, STDOUT,
and STDERR are also in C<:encoding(UTF-8)>.  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 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-layers C<:bytes> and C<:crlf> are available.

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 layers 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<PerlIO::Layer> C<find> which is
implemented as XS code.  It is called by C<import> to validate the
layers:

PerlIO::Layer::->find("perlio")

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<PerlIO>,
L<encoding>

=cut

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