#!/usr/bin/perl

use strict;
use warnings;

use Data::Dumper;

sub comp
{
	my( $sub, $var, $list, @x ) = @_;

	my @l;

	no strict 'refs';
	for ( $list->() )
	{
		${"::$var"} = $_;
		push @l, @x ? comp( $sub, @x ) : $sub->();
	} # for

	return @l;
} # comp

my @tripel = comp sub{
	$::i**2 == $::j**2 + $::k**2
		? [$::k, $::j, $::i]
		: ()
},	'i' => sub{ 1..  10 },
	'j' => sub{ 1..$::i },
	'k' => sub{ 1..$::j };

print Dumper( \@tripel ), "\n";