PerlIO::via::UnComment - PerlIO layer for removing comments

 use PerlIO::via::UnComment;

 open( my $in,'<:via(UnComment)','file.pm' )
  or die "Can't open file.pm for reading: $!\n";

 open( my $out,'>:via(UnComment)','file.pm' )
  or die "Can't open file.pm for writing: $!\n";

 #!/usr/bin/perl
 use PerlIO::via::UnComment;
 binmode( STDIN,':via(UnComment)' ); # could also be STDOUT
 print while <STDIN>;

 #!/usr/bin/perl
 use PerlIO::via::UnComment;
 use PerlIO::via::UnPod;
 binmode( STDIN,':via(UnComment):via(UnPod)' ); # could also be STDOUT
 print while <STDIN>;

 (none)

package PerlIO::via::UnComment;

# Set the version info
# Make sure we do things by the book from now on

$VERSION = '0.03';
use strict;

# Satisfy -require-

1;

#-----------------------------------------------------------------------

# Subroutines for standard Perl features

#-----------------------------------------------------------------------
#  IN: 1 class to bless with
#      2 mode string (ignored)
#      3 file handle of PerlIO layer below (ignored)
# OUT: 1 blessed object

sub PUSHED { 

# Die now if strange mode
# Create the object

#    die "Can only read or write with removing comments" unless $_[1] =~ m#^[rw]$#;
    bless \*PUSHED,$_[0];
} #PUSHED

#-----------------------------------------------------------------------
#  IN: 1 instantiated object
#      2 handle to read from
# OUT: 1 processed string (if any)

sub FILL {

# Create local copy of $_
# While there are lines to be read from the handle
#  Return the line if it doesn't start with a '#'
# Return indicating end reached

    local( $_ );
    while (defined( $_ = readline( $_[1] ) )) {
        return $_ unless /^#/;
    }
    undef;
} #FILL

#-----------------------------------------------------------------------
#  IN: 1 instantiated object
#      2 buffer to be written
#      3 handle to write to
# OUT: 1 number of bytes written

sub WRITE {

# For all of the lines in this bunch (includes delimiter at end)
#  Reloop if it is a comment line
#  Print the line, return now if failed
# Return total number of octets handled

    foreach (split( m#(?<=$/)#,$_[1] )) {
	next if /^#/;
        return -1 unless print {$_[2]} $_;
    }
    length( $_[1] );
} #WRITE

#-----------------------------------------------------------------------

__END__