[perl5.git] / lib / PerlIO.pm

package PerlIO;

# Map layer name to package that defines it
my %alias = (encoding => 'Encode');

sub import
{
 my $class = shift;
 while (@_)
  {
   my $layer = shift;
   if (exists $alias{$layer})
    {
     $layer = $alias{$layer}
    }
   else
    {
     $layer = "${class}::$layer";
    }
   eval "require $layer";
   warn $@ if $@;
  }
}

1;
__END__

=head1 NAME

PerlIO - On demand loader for PerlIO::* name space

=head1 SYNOPSIS

  open($fh,">:foo",...)

=head1 DESCRIPTION

When an undefined layer 'foo' is encountered in an C<open> or C<binmode> layer
specification then C code performs the equivalent of:

  use PerlIO 'foo';

The perl code in PerlIO.pm then attempts to locate a layer by doing

  require PerlIO::foo;

Otherwise the C<PerlIO> package is a place holder for additional PerLIO related
functions.


=cut
Commit	Line	Data
1141d9f8 NIS	1	package PerlIO;
	2
	3	# Map layer name to package that defines it
	4	my %alias = (encoding => 'Encode');
	5
	6	sub import
	7	{
	8	my $class = shift;
	9	while (@_)
	10	{
	11	my $layer = shift;
	12	if (exists $alias{$layer})
	13	{
	14	$layer = $alias{$layer}
	15	}
	16	else
	17	{
	18	$layer = "${class}::$layer";
	19	}
	20	eval "require $layer";
	21	warn $@ if $@;
	22	}
	23	}
	24
	25	1;
	26	__END__
b3d30bf7 NIS	27
	28	=head1 NAME
	29
	30	PerlIO - On demand loader for PerlIO::* name space
	31
	32	=head1 SYNOPSIS
	33
	34	open($fh,">:foo",...)
	35
	36	=head1 DESCRIPTION
	37
	38	When an undefined layer 'foo' is encountered in an C<open> or C<binmode> layer
	39	specification then C code performs the equivalent of:
	40
	41	use PerlIO 'foo';
	42
	43	The perl code in PerlIO.pm then attempts to locate a layer by doing
	44
	45	require PerlIO::foo;
	46
	47	Otherwise the C<PerlIO> package is a place holder for additional PerLIO related
	48	functions.
	49
	50
	51	=cut
	52
	53