Added new method to pairs and holders

2 files changed, 52 insertions, 32 deletions

diff --git a/BJC-Utils2/src/main/java/bjc/utils/parserutils/AST.java b/BJC-Utils2/src/main/java/bjc/utils/parserutils/AST.java
index 88b4862..b6c4d8c 100644
--- a/BJC-Utils2/src/main/java/bjc/utils/parserutils/AST.java
+++ b/BJC-Utils2/src/main/java/bjc/utils/parserutils/AST.java
@@ -361,4 +361,26 @@ public class AST<T> {
 			action.accept(token);
 		}
 	}
+
+	/**
+	 * Change the type of nodes in the tree without changing the structure
+	 * 
+	 * @param <E>
+	 *            The new node type
+	 * @param nodeTransform
+	 *            The transform to apply to leaf nodes
+	 * @param operatorTransform
+	 *            The transform to apply to operator nodes
+	 * @return An AST with the node types transformed
+	 */
+	public <E> AST<E> rebuildTree(Function<T, E> nodeTransform,
+			Function<T, E> operatorTransform) {
+		return collapse((leafNode) -> {
+			E transformedNode = nodeTransform.apply(leafNode);
+			return new AST<>(transformedNode);
+		}, (operator) -> (AST<E> newLeft, AST<E> newRight) -> {
+			return new AST<>(operatorTransform.apply(operator), newLeft,
+					newRight);
+		}, (resultValue) -> resultValue);
+	}
 }
diff --git a/BJC-Utils2/src/main/java/bjc/utils/parserutils/TreeConstructor.java b/BJC-Utils2/src/main/java/bjc/utils/parserutils/TreeConstructor.java
index 46e4da4..68ec70e 100644
--- a/BJC-Utils2/src/main/java/bjc/utils/parserutils/TreeConstructor.java
+++ b/BJC-Utils2/src/main/java/bjc/utils/parserutils/TreeConstructor.java
@@ -28,40 +28,38 @@ public class TreeConstructor {
 			}
 
 			@Override
-			public IPair<Deque<AST<T>>, AST<T>>
-					apply(IPair<Deque<AST<T>>, AST<T>> pair) {
-				Deque<AST<T>> queuedASTs =
-						pair.merge((queue, currentAST) -> queue);
-
-				AST<T> mergedAST = pair.merge((queue, currentAST) -> {
-					AST<T> newAST;
-
-					if (isSpecialOperator.test(element)) {
-						newAST = handleSpecialOperator.apply(queue);
-					} else {
-						if (queue.size() < 2) {
-							throw new IllegalStateException(
-									"Attempted to parse binary operator without enough operands.\n"
-											+ "Problem operator is "
-											+ element
-											+ "\nPossible operand is: \n\t"
-											+ queue.peek());
-						}
-
-						AST<T> rightAST = queue.pop();
-						AST<T> leftAST = queue.pop();
-
-						newAST = new AST<>(element, leftAST, rightAST);
+			public IPair<Deque<AST<T>>, AST<T>> apply(
+					IPair<Deque<AST<T>>, AST<T>> pair) {
+				return pair.bind((queuedASTs, currentAST) -> {
+					return handleOperator(queuedASTs);
+				});
+			}
+
+			private IPair<Deque<AST<T>>, AST<T>> handleOperator(
+					Deque<AST<T>> queuedASTs) {
+				AST<T> newAST;
+
+				if (isSpecialOperator.test(element)) {
+					newAST = handleSpecialOperator.apply(queuedASTs);
+				} else {
+					if (queuedASTs.size() < 2) {
+						throw new IllegalStateException(
+								"Attempted to parse binary operator without enough operands.\n"
+										+ "Problem operator is "
+										+ element
+										+ "\nPossible operand is: \n\t"
+										+ queuedASTs.peek());
 					}
 
-					queue.push(newAST);
-					return newAST;
-				});
+					AST<T> rightAST = queuedASTs.pop();
+					AST<T> leftAST = queuedASTs.pop();
+
+					newAST = new AST<>(element, leftAST, rightAST);
+				}
 
-				Pair<Deque<AST<T>>, AST<T>> newPair =
-						new Pair<>(queuedASTs, mergedAST);
+				queuedASTs.push(newAST);
 
-				return newPair;
+				return new Pair<>(queuedASTs, newAST);
 			}
 		}
 
@@ -162,8 +160,8 @@ public class TreeConstructor {
 					"Special operator determiner must not be null");
 		}
 
-		GenHolder<IPair<Deque<AST<T>>, AST<T>>> initialState =
-				new GenHolder<>(new Pair<>(new LinkedList<>(), null));
+		GenHolder<IPair<Deque<AST<T>>, AST<T>>> initialState = new GenHolder<>(
+				new Pair<>(new LinkedList<>(), null));
 
 		tokens.forEach(
 				new TokenTransformer<>(initialState, operatorPredicate,