#!/your/perl/here

use strict;
use warnings;
use Getopt::Declare;
our $options;
 
$options = Getopt::Declare->new( <<'OPTIONS' );
  -one <one:i>	First parameter
  { defer
    { reject ( $one > $two 
        => '\$one ($one) > \$two ($two)' )
    }
  }

  -two <two:i>	Second parameter
  { defer
    { reject ( $one > $two 
        => '\$one ($one) > \$two ($two)' )
    }
  }
OPTIONS

print "one = $options->{-one}\n";
print "two = $options->{-two}\n";

__INVOKED_WITH__
perl declare.pl -one 10 -two 20

__OUTPUT__
Error: in generated parser code:
Global symbol "$two" requires explicit package name at (eval 7) line 100.
Global symbol "$one" requires explicit package name at (eval 7) line 144.

##</code><code>##

sub validate
{
	my $options = shift;
	$options->{-one} = 1 unless ( exists( $options->{-one} ) );
	$options->{-two} = 2 unless ( exists( $options->{-two} ) );
	
	die "Error: -one ($options->{-one}) > -two ($options->{-two}), "
	  if ( $options->{-one} > $options->{-two} );
}
$options = Getopt::Declare->new( <<'OPTIONS' );
...
OPTIONS
validate( $options );