Haskell n-ary tree traversal

Question

I\'m pretty new to Haskell and I\'m trying to work out how to traverse a n-ary tree. As output I\'m looking to get a list of Leaf values (as the branches have no value), so for

Answer 1

Traversing a tree means traversing all subtrees and flattening the resulting lists into one.

This translates to

travTree (Branch branches) = concat $ map travTree branches

Note that there are even more concise notations like branches >>= travTree or concatMap travTree branches for the right hand side of this definition, but I consider the above one to be the clearest.

Edit: Reintroducing the list-comprehension version for the sake of completeness:

travTree (Branch branches) = [ elem | br <- branches, elem <- travTree br ]