Tree (core 3.2 API)

java.lang.Object
- fj.data.Tree<A>

All Implemented Interfaces:

java.lang.Iterable<A>
```
public final class Tree<A>
extends java.lang.Object
implements java.lang.Iterable<A>
```
Provides a lazy, immutable, non-empty, multi-way tree (a rose tree).

Method Summary

Methods
Modifier and Type	Method and Description
`static <A,B> Tree<B>`	`bottomUp(Tree<A> t, F<P2<A,Stream<B>>,B> f)` Folds a Tree into a Tree by applying the function f from the bottom of the Tree to the top
`<B> Tree<B>`	`cobind(F<Tree<A>,B> f)` Applies the given function to all subtrees of this tree, returning a tree of the results (comonad pattern).
`Tree<Tree<A>>`	`cojoin()` Expands this tree into a tree of trees, with this tree as the root label, and subtrees as the labels of child nodes (comonad pattern).
`java.lang.String`	`draw(Show<A> s)` Draws a 2-dimensional representation of a tree.
`static <A> F<Tree<A>,Stream<A>>`	`flatten_()` flatten :: Tree a -> [a] flatten t = squish t [] where squish (Node x ts) xs = x:Prelude.foldr squish xs ts Puts the elements of the tree into a Stream, in pre-order.
`Stream<A>`	`flatten()` Puts the elements of the tree into a Stream, in pre-order.
`static <A,B> F<F<A,B>,F<Tree<A>,Tree<B>>>`	`fmap_()` Provides a transformation to lift any function so that it maps over Trees.
`<B> Tree<B>`	`fmap(F<A,B> f)` Maps the given function over this tree.
`static <A,B> F<Tree<A>,B>`	`foldMap_(F<A,B> f, Monoid<B> m)` Provides a function that folds a tree with the given monoid.
`<B> B`	`foldMap(F<A,B> f, Monoid<B> m)` Folds this tree using the given monoid.
`java.util.Iterator<A>`	`iterator()` Returns an iterator for this tree.
`static <A> Tree<A>`	`leaf(A root)` Creates a nullary tree.
`Stream<Stream<A>>`	`levels()` Provides a stream of the elements of the tree at each level, in level order.
`static <A> F<A,F<P1<Stream<Tree<A>>>,Tree<A>>>`	`node()` First-class constructor of trees.
`static <A> Tree<A>`	`node(A root, List<Tree<A>> forest)` Creates a new n-ary given a root and a subforest of length n.
`static <A> Tree<A>`	`node(A root, P1<Stream<Tree<A>>> forest)` Creates a new tree given a root and a (potentially infinite) subforest.
`static <A> Tree<A>`	`node(A root, Stream<Tree<A>> forest)` Creates a new tree given a root and a (potentially infinite) subforest.
`static <A> F<Tree<A>,A>`	`root_()` Provides a transformation from a tree to its root.
`A`	`root()` Returns the root element of the tree.
`static <A> Show<Tree<A>>`	`show2D(Show<A> s)` Provides a show instance that draws a 2-dimensional representation of a tree.
`static <A> F<Tree<A>,P1<Stream<Tree<A>>>>`	`subForest_()` Provides a transformation from a tree to its subforest.
`P1<Stream<Tree<A>>>`	`subForest()` Returns a stream of the tree's subtrees.
`java.util.Collection<A>`	`toCollection()` Projects an immutable collection of this tree.
`static <A,B> F<B,Tree<A>>`	`unfoldTree(F<B,P2<A,P1<Stream<B>>>> f)` Builds a tree from a seed value.
`<B,C> Tree<C>`	`zipWith(Tree<B> bs, F<A,F<B,C>> f)` Zips this tree with another, using the given function.
`<B,C> Tree<C>`	`zipWith(Tree<B> bs, F2<A,B,C> f)` Zips this tree with another, using the given function.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
 - iterator
```
public java.util.Iterator<A> iterator()
```
 Returns an iterator for this tree. This method exists to permit the use in a for-each loop.
 
 Specified by:
 
 iterator in interface java.lang.Iterable<A>
 
 Returns:
 A iterator for this tree.
 - leaf
```
public static <A> Tree<A> leaf(A root)
```
 Creates a nullary tree.
 
 Parameters:
 root - The root element of the tree.
 
 Returns:
 A nullary tree with the root element in it.
 - node
```
public static <A> Tree<A> node(A root,
 P1<Stream<Tree<A>>> forest)
```
 Creates a new tree given a root and a (potentially infinite) subforest.
 
 Parameters:
 root - The root element of the tree.
 forest - A stream of the tree's subtrees.
 
 Returns:
 A newly sprouted tree.
 - node
```
public static <A> Tree<A> node(A root,
 Stream<Tree<A>> forest)
```
 Creates a new tree given a root and a (potentially infinite) subforest.
 
 Parameters:
 root - The root element of the tree.
 forest - A stream of the tree's subtrees.
 
 Returns:
 A newly sprouted tree.
 - node
```
public static <A> Tree<A> node(A root,
 List<Tree<A>> forest)
```
 Creates a new n-ary given a root and a subforest of length n.
 
 Parameters:
 root - The root element of the tree.
 forest - A list of the tree's subtrees.
 
 Returns:
 A newly sprouted tree.
 - node
```
public static <A> F<A,F<P1<Stream<Tree<A>>>,Tree<A>>> node()
```
 First-class constructor of trees.
 
 Returns:
 A function that constructs an n-ary tree given a root and a subforest or length n.
 - root
```
public A root()
```
 Returns the root element of the tree.
 
 Returns:
 The root element of the tree.
 - subForest
```
public P1<Stream<Tree<A>>> subForest()
```
 Returns a stream of the tree's subtrees.
 
 Returns:
 A stream of the tree's subtrees.
 - root_
```
public static <A> F<Tree<A>,A> root_()
```
 Provides a transformation from a tree to its root.
 
 Returns:
 A transformation from a tree to its root.
 - subForest_
```
public static <A> F<Tree<A>,P1<Stream<Tree<A>>>> subForest_()
```
 Provides a transformation from a tree to its subforest.
 
 Returns:
 A transformation from a tree to its subforest.
 - flatten
```
public Stream<A> flatten()
```
 Puts the elements of the tree into a Stream, in pre-order.
 
 Returns:
 The elements of the tree in pre-order.
 - flatten_
```
public static <A> F<Tree<A>,Stream<A>> flatten_()
```
 flatten :: Tree a -> [a] flatten t = squish t [] where squish (Node x ts) xs = x:Prelude.foldr squish xs ts Puts the elements of the tree into a Stream, in pre-order.
 
 Returns:
 The elements of the tree in pre-order.
 - levels
```
public Stream<Stream<A>> levels()
```
 Provides a stream of the elements of the tree at each level, in level order.
 
 Returns:
 The elements of the tree at each level.
 - fmap
```
public  Tree fmap(F<A,B> f)
```
 Maps the given function over this tree.
 
 Parameters:
 f - The function to map over this tree.
 
 Returns:
 The new Tree after the function has been applied to each element in this Tree.
 - fmap_
```
public static <A,B> F<F<A,B>,F<Tree<A>,Tree>> fmap_()
```
 Provides a transformation to lift any function so that it maps over Trees.
 
 Returns:
 A transformation to lift any function so that it maps over Trees.
 - foldMap
```
public  B foldMap(F<A,B> f,
 Monoid m)
```
 Folds this tree using the given monoid.
 
 Parameters:
 f - A transformation from this tree's elements, to the monoid.
 m - The monoid to fold this tree with.
 
 Returns:
 The result of folding the tree with the given monoid.
 - toCollection
```
public java.util.Collection<A> toCollection()
```
 Projects an immutable collection of this tree.
 
 Returns:
 An immutable collection of this tree.
 - foldMap_
```
public static <A,B> F<Tree<A>,B> foldMap_(F<A,B> f,
 Monoid m)
```
 Provides a function that folds a tree with the given monoid.
 
 Parameters:
 f - A transformation from a tree's elements to the monoid.
 m - A monoid to fold the tree with.
 
 Returns:
 A function that, given a tree, folds it with the given monoid.
 - unfoldTree
```
public static <A,B> F<B,Tree<A>> unfoldTree(F<B,P2<A,P1<Stream>>> f)
```
 Builds a tree from a seed value.
 
 Parameters:
 f - A function with which to build the tree.
 
 Returns:
 A function which, given a seed value, yields a tree.
 - cobind
```
public  Tree cobind(F<Tree<A>,B> f)
```
 Applies the given function to all subtrees of this tree, returning a tree of the results (comonad pattern).
 
 Parameters:
 f - A function to bind across all the subtrees of this tree.
 
 Returns:
 A new tree, with the results of applying the given function to each subtree of this tree. The result of applying the function to the entire tree is the root label, and the results of applying to the root's children are labels of the root's subforest, etc.
 - cojoin
```
public Tree<Tree<A>> cojoin()
```
 Expands this tree into a tree of trees, with this tree as the root label, and subtrees as the labels of child nodes (comonad pattern).
 
 Returns:
 A tree of trees, with this tree as its root label, and subtrees of this tree as the labels of its child nodes.
 - draw
```
public java.lang.String draw(Show<A> s)
```
 Draws a 2-dimensional representation of a tree.
 
 Parameters:
 s - A show instance for the elements of the tree.
 
 Returns:
 a String showing this tree in two dimensions.
 - show2D
```
public static <A> Show<Tree<A>> show2D(Show<A> s)
```
 Provides a show instance that draws a 2-dimensional representation of a tree.
 
 Parameters:
 s - A show instance for the elements of the tree.
 
 Returns:
 a show instance that draws a 2-dimensional representation of a tree.
 - zipWith
```
public <B,C> Tree<C> zipWith(Tree bs,
 F2<A,B,C> f)
```
 Zips this tree with another, using the given function. The resulting tree is the structural intersection of the two trees.
 
 Parameters:
 bs - A tree to zip this tree with.
 f - A function with which to zip together the two trees.
 
 Returns:
 A new tree of the results of applying the given function over this tree and the given tree, position-wise.
 - zipWith
```
public <B,C> Tree<C> zipWith(Tree bs,
 F<A,F<B,C>> f)
```
 Zips this tree with another, using the given function. The resulting tree is the structural intersection of the two trees.
 
 Parameters:
 bs - A tree to zip this tree with.
 f - A function with which to zip together the two trees.
 
 Returns:
 A new tree of the results of applying the given function over this tree and the given tree, position-wise.
 - bottomUp
```
public static <A,B> Tree bottomUp(Tree<A> t,
 F<P2<A,Stream>,B> f)
```
 Folds a Tree into a Tree by applying the function f from the bottom of the Tree to the top
 
 Parameters:
 t - A tree to fold from the bottom to the top.
 f - A function transforming the current node and a stream of already transformed nodes (its children) into a new node
 
 Returns:
 The folded tree

Class Tree<A>

Method Summary

Methods inherited from class java.lang.Object

Method Detail

iterator

leaf

node

node

node

node

root

subForest

root_

subForest_

flatten

flatten_

levels

fmap

fmap_

foldMap

toCollection

foldMap_

unfoldTree

cobind

cojoin

draw

show2D

zipWith

zipWith

bottomUp