#!/usr/bin/perl
use strict;
use warnings;
$|++;


sub to_zero_or_below 
{
	## must have a two element list to process
	return unless 2 <= @_;
	for my $index ( 1..$#_ )
	{
		## skip unless i've decended to zero or below
		next unless $_[$index - 1] > 0 and $_[$index] <= 0;
		## return the remainder of the list
		return @_[$index..$#_];
	}
}

my @data= ( -3, -1, 1, 3, 2, 1, 0, -1, -2 );

## zero present
print $_, $/ 
	for to_zero_or_below( @data );

print "~~~\n";

## no zero
print $_, $/
	for to_zero_or_below( reverse @data );