=== haskell ===


data Tree a = Leaf a | Node (Tree a) (Tree a)
    deriving (Show, Eq)
 
fringe :: Tree a -> [a]
fringe (Leaf x) = [x]
fringe (Node n1 n2) = fringe n1 ++ fringe n2
 
sameFringe :: (Eq a) => Tree a -> Tree a -> Bool
sameFringe t1 t2 = fringe t1 == fringe t2

 

=== Perl 6 ===

sub fringe ($tree) {

    multi sub fringey (Pair $node) { fringey $_ for $node.kv }
    multi sub fringey ( Any $leaf) { take $leaf }                

    (gather fringey $tree), Cool;
}
 
sub samefringe ($a, $b) { all fringe($a) Z=== fringe($b) }