Added new option to top-down travers

3 files changed, 45 insertions, 2 deletions

diff --git a/BJC-Utils2/src/main/java/bjc/utils/funcdata/ITree.java b/BJC-Utils2/src/main/java/bjc/utils/funcdata/ITree.java
index 7f28682..bbcefd3 100644
--- a/BJC-Utils2/src/main/java/bjc/utils/funcdata/ITree.java
+++ b/BJC-Utils2/src/main/java/bjc/utils/funcdata/ITree.java
@@ -155,4 +155,24 @@ public interface ITree<ContainedType> {
 	public ITree<ContainedType> topDownTransform(
 			Function<ContainedType, TopDownTransformResult> transformPicker,
 			UnaryOperator<ITree<ContainedType>> transformer);
+
+	/**
+	 * Get the specified child of this tree
+	 * 
+	 * @param childNo
+	 *            The number of the child to get
+	 * @return The specified child of this tree
+	 */
+	default ITree<ContainedType> getChild(int childNo) {
+		return transformChild(childNo, (child) -> child);
+	}
+
+	/**
+	 * Get the data stored in this node
+	 * 
+	 * @return The data stored in this node
+	 */
+	default ContainedType getHead() {
+		return transformHead((head) -> head);
+	}
 }
diff --git a/BJC-Utils2/src/main/java/bjc/utils/funcdata/TopDownTransformResult.java b/BJC-Utils2/src/main/java/bjc/utils/funcdata/TopDownTransformResult.java
index 9aec2b9..f48a90a 100644
--- a/BJC-Utils2/src/main/java/bjc/utils/funcdata/TopDownTransformResult.java
+++ b/BJC-Utils2/src/main/java/bjc/utils/funcdata/TopDownTransformResult.java
@@ -18,5 +18,9 @@ public enum TopDownTransformResult {
 	/**
 	 * Ignore this node, and traverse its children
 	 */
-	PASSTHROUGH;
+	PASSTHROUGH,
+	/**
+	 * Traverse this nodes children, then transform it
+	 */
+	PUSHDOWN;
 }
diff --git a/BJC-Utils2/src/main/java/bjc/utils/funcdata/Tree.java b/BJC-Utils2/src/main/java/bjc/utils/funcdata/Tree.java
index 03a1f93..cd43df7 100644
--- a/BJC-Utils2/src/main/java/bjc/utils/funcdata/Tree.java
+++ b/BJC-Utils2/src/main/java/bjc/utils/funcdata/Tree.java
@@ -60,7 +60,15 @@ public class Tree<ContainedType> implements ITree<ContainedType> {
 		}
 	}
 
-	private Tree(ContainedType leafToken,
+	/**
+	 * Create a new tree node with the specified children
+	 * 
+	 * @param leafToken
+	 *            The data to hold in this node
+	 * @param childrn
+	 *            A list of children for this node
+	 */
+	public Tree(ContainedType leafToken,
 			IFunctionalList<ITree<ContainedType>> childrn) {
 		data = leafToken;
 
@@ -286,6 +294,17 @@ public class Tree<ContainedType> implements ITree<ContainedType> {
 				return this;
 			case TRANSFORM:
 				return transformer.apply(this);
+			case PUSHDOWN:
+				result = new Tree<>(data);
+
+				if (hasChildren) {
+					children.forEach((child) -> {
+						result.addChild(child.topDownTransform(
+								transformPicker, transformer));
+					});
+				}
+
+				return transformer.apply(result);
 			default:
 				throw new IllegalArgumentException(
 						"Recieved unknown transform result "