diff options
Diffstat (limited to 'src/main/java/au/id/zancanaro/RoseTree.java')
-rw-r--r-- | src/main/java/au/id/zancanaro/RoseTree.java | 103 |
1 files changed, 0 insertions, 103 deletions
diff --git a/src/main/java/au/id/zancanaro/RoseTree.java b/src/main/java/au/id/zancanaro/RoseTree.java deleted file mode 100644 index 458d441..0000000 --- a/src/main/java/au/id/zancanaro/RoseTree.java +++ /dev/null @@ -1,103 +0,0 @@ -package au.id.zancanaro; - -import java.io.IOException; -import java.io.Writer; -import java.util.Collections; -import java.util.Iterator; -import java.util.function.Function; -import java.util.function.Predicate; - -public class RoseTree<T> { - private final T value; - private final Iterable<RoseTree<T>> children; - - public RoseTree(T value, Iterable<RoseTree<T>> children) { - this.value = value; - this.children = children; - } - - public T getValue() { - return value; - } - - public Iterator<RoseTree<T>> getChildren() { - return children.iterator(); - } - - public static <T> RoseTree<T> pure(T value) { - return new RoseTree<>(value, Collections.emptyList()); - } - - public static <T> RoseTree<T> join(RoseTree<RoseTree<T>> tree) { - return new RoseTree<>( - tree.getValue().getValue(), - () -> Iterators.concat( - Iterators.mappingIterator(RoseTree::join, tree.children.iterator()), - tree.getValue().children.iterator())); - } - - public static <T> Iterator<RoseTree<T>[]> permutations(RoseTree<T>[] trees) { - return Iterators.flatten(Iterators.rangeIterator(trees.length, index -> - Iterators.mappingIterator(child -> { - @SuppressWarnings("unchecked") - RoseTree<T>[] result = (RoseTree<T>[]) new RoseTree[trees.length]; - for (int i = 0; i < trees.length; ++i) { - result[i] = (i == index ? child : trees[i]); - } - return result; - }, trees[index].getChildren()) - )); - } - - public static <T, R> RoseTree<R> zip(Function<T[], R> fn, RoseTree<T>[] trees) { - @SuppressWarnings("unchecked") - T[] heads = (T[]) new Object[trees.length]; - for (int i = 0; i < trees.length; ++i) { - heads[i] = trees[i].getValue(); - } - return new RoseTree<>( - fn.apply(heads), - () -> Iterators.mappingIterator( - roses -> RoseTree.zip(fn, roses), - RoseTree.permutations(trees))); - } - - public <R> RoseTree<R> fmap(Function<T, R> f) { - return new RoseTree<>( - f.apply(this.value), - () -> Iterators.mappingIterator(tree -> tree.fmap(f), this.children.iterator())); - } - - public <R> RoseTree<R> flatmap(Function<T, RoseTree<R>> f) { - return RoseTree.join(this.fmap(f)); - } - - public RoseTree<T> filter(Predicate<T> predicate) { - if (predicate.test(this.getValue())) { - return new RoseTree<>( - this.getValue(), - () -> Iterators.mappingIterator(tree -> tree.filter(predicate), - Iterators.filteringIterator( - tree -> predicate.test(tree.getValue()), - this.getChildren()))); - } else { - throw new IllegalArgumentException("Current value doesn't match predicate: whoops!"); - } - } - - @SuppressWarnings("unused") - public void print(Writer output) throws IOException { - print(output, Object::toString); - } - - @SuppressWarnings("unused") - public void print(Writer output, Function<T, String> toString) throws IOException { - output.write(toString.apply(this.getValue())); - output.write('['); - for (RoseTree<T> child : children) { - child.print(output, toString); - } - output.write(']'); - output.flush(); - } -} |