Tree.Extra provides functions for working with rose trees as defined
in [zwilias/elm-rosetree](attach gte targetNode subTree tree), e.g,
removeSubTree, moveSubTree, and spanningTree. Here is an example:
> import Tree -- from zwilias/elm-rosetree
> import Tree.Extra exposing(..)
> s = Tree.singleton
> t = Tree.tree
> a = t 1 [ t 2 [ s 3, t 4 [s 5, s 6]]]
Tree 1 [Tree 2 [Tree 3 [],Tree 4 [Tree 5 [],Tree 6 []]]]
> moveSubTree 4 1 a
Just (Tree 1 [ Tree 2 [Tree 3 []]
, Tree 4 [Tree 5 [],Tree 6 []]])In certain cases, one assumes given a function that defines a partial order on nodes, or better said, labels of nodes:
bigger : a -> a -> Bool
For Tree Int, one can use
bigger = (>)
See the function attach for an example of this.