示例#1
0
 /**
  * Provides a stream of the elements of the tree at each level, in level order.
  *
  * @return The elements of the tree at each level.
  */
 public Stream<Stream<A>> levels() {
   final F<Stream<Tree<A>>, Stream<Tree<A>>> flatSubForests =
       Stream.<Tree<A>, Tree<A>>bind_()
           .f(compose(P1.<Stream<Tree<A>>>__1(), Tree.<A>subForest_()));
   final F<Stream<Tree<A>>, Stream<A>> roots = Stream.<Tree<A>, A>map_().f(Tree.<A>root_());
   return iterateWhile(flatSubForests, Stream.<Tree<A>>isNotEmpty_(), single(this)).map(roots);
 }
示例#2
0
 /**
  * Folds a Tree<A> into a Tree<B> by applying the function f from the bottom of the Tree to the
  * top
  *
  * @param t A tree to fold from the bottom to the top.
  * @param f A function transforming the current node and a stream of already transformed nodes
  *     (its children) into a new node
  * @return The folded tree
  */
 public static <A, B> Tree<B> bottomUp(Tree<A> t, final F<P2<A, Stream<B>>, B> f) {
   final F<Tree<A>, Tree<B>> recursiveCall = a -> bottomUp(a, f);
   final Stream<Tree<B>> tbs = t.subForest()._1().map(recursiveCall);
   return node(f.f(P.p(t.root(), tbs.map(Tree.getRoot()))), tbs);
 }
示例#3
0
 /**
  * Maps the given function over this tree.
  *
  * @param f The function to map over this tree.
  * @return The new Tree after the function has been applied to each element in this Tree.
  */
 public <B> Tree<B> fmap(final F<A, B> f) {
   return node(
       f.f(root()), subForest().map(Stream.<Tree<A>, Tree<B>>map_().f(Tree.<A, B>fmap_().f(f))));
 }