Fixing extra -I's with PERL_CORE

[p5sagit/p5-mst-13.2.git] / lib / open.pm

diff --git a/lib/open.pm b/lib/open.pm
index 1aef904..3a08b79 100644 (file)
--- a/lib/open.pm
+++ b/lib/open.pm
@@ -2,15 +2,7 @@ package open;
 use Carp;
 $open::hint_bits = 0x20000;
 
-# layers array and hash mainly manipulated by C code in perlio.c
-use vars qw(%layers @layers);
-
-# Populate hash in non-PerlIO case
-%layers = (crlf => 1, raw => 0) unless (@layers);
-
-# warn join(',',keys %layers);
-
-our $VERSION = '1.00';
+our $VERSION = '1.01';
 
 sub import {
     my ($class,@args) = @_;
@@ -25,7 +17,7 @@ sub import {
        my @val;
        foreach my $layer (split(/\s+/,$discp)) {
             $layer =~ s/^://;
-           unless(exists $layers{$layer}) {
+           unless(PerlIO::Layer::->find($layer)) {
                carp("Unknown discipline layer '$layer'");
            }
            push(@val,":$layer");
@@ -59,60 +51,45 @@ open - perl pragma to set default disciplines for input and output
 
 =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).
+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.
+I/O operations.  Any open(), readpipe() (aka qx//) and similar
+operators found within the lexical scope of this pragma will use the
+declared defaults.
 
-When open() is given an explicit list of layers they are appended to the
-list declared using this pragma.
+When open() is given an explicit list of layers they are appended to
+the list declared using this pragma.
 
 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.
+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.
+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 are two package variables C<%layers> and C<@layers> which
-are mainly manipulated by C code in F<perlio.c>, but are visible
-to the nosy:
-
-  print "Have ",join(',',keys %open::layers),"\n";
-  print "Using ",join(',',@open::layers),"\n";
-
-The C<%open::layers> hash is a record of the available "layers" that may be pushed
-onto a C<PerlIO> stream. The values of the hash are perl objects, of class C<PerlIO::Layer>
-which are created by the C code in F<perlio.c>. As yet there is nothing useful you
-can do with the objects at the perl level.
-
-The C<@open::layers> array is the current set of layers and their arguments.
-The array consists of layer => argument pairs and I<must> always have even number of
-entries and the even entries I<must> be C<PerlIO::Layer> objects or perl will "die"
-when it attempts to open a filehandle. In most cases the odd entry will be C<undef>,
-but in the case of (say) ":encoding(iso-8859-1)" it will be 'iso-8859-1'. These
-argument entries are currently restricted to being strings.
+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:
 
-When a new C<PerlIO> stream is opened, the C code looks at the
-array to determine the default layers to be pushed. So with care it is possible
-to manipulate the default layer "stack":
+   PerlIO::Layer::->find("perlio")
 
-    splice(@PerlIO::layers,-2,2);
-    push(@PerlIO::layers,$PerlIO::layers{'stdio'} => undef);
+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