1 files changed, 64 insertions, 0 deletions
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/ArithmeticCollapser.java b/dice-lang/src/main/java/bjc/dicelang/ast/ArithmeticCollapser.java
new file mode 100644
index 0000000..5ad0a0f
--- /dev/null
+++ b/dice-lang/src/main/java/bjc/dicelang/ast/ArithmeticCollapser.java
@@ -0,0 +1,64 @@
+package bjc.dicelang.ast;
+
+import java.util.function.BinaryOperator;
+
+import bjc.dicelang.ast.nodes.IDiceASTNode;
+import bjc.dicelang.ast.nodes.OperatorDiceNode;
+import bjc.utils.data.IPair;
+import bjc.utils.data.Pair;
+import bjc.utils.funcdata.IFunctionalList;
+import bjc.utils.funcdata.ITree;
+import bjc.utils.funcdata.Tree;
+
+/**
+ * Responsible for collapsing arithmetic operators
+ * 
+ * @author ben
+ *
+ */
+final class ArithmeticCollapser
+		implements IOperatorCollapser {
+	private OperatorDiceNode		type;
+
+	private BinaryOperator<Integer>	valueOp;
+
+	public ArithmeticCollapser(OperatorDiceNode type,
+			BinaryOperator<Integer> valueOp) {
+		this.type = type;
+		this.valueOp = valueOp;
+	}
+
+	@Override
+	public IPair<Integer, ITree<IDiceASTNode>> apply(
+			IFunctionalList<IPair<Integer, ITree<IDiceASTNode>>> nodes) {
+		IPair<Integer, ITree<IDiceASTNode>> initState =
+				new Pair<>(0, new Tree<>(type));
+
+		BinaryOperator<IPair<Integer, ITree<IDiceASTNode>>> reducer =
+				(accumulatedState, currentState) -> {
+					return reduceStates(accumulatedState,
+							currentState);
+				};
+
+		return nodes.reduceAux(initState, reducer, (state) -> state);
+	}
+
+	private IPair<Integer, ITree<IDiceASTNode>> reduceStates(
+			IPair<Integer, ITree<IDiceASTNode>> accumulatedState,
+			IPair<Integer, ITree<IDiceASTNode>> currentState) {
+		return accumulatedState
+				.bind((accumulatedValue, accumulatedTree) -> {
+					return currentState
+							.bind((currentValue, currentTree) -> {
+								accumulatedTree.addChild(currentTree);
+
+								Integer combinedValue =
+										valueOp.apply(accumulatedValue,
+												currentValue);
+
+								return new Pair<>(combinedValue,
+										accumulatedTree);
+							});
+				});
+	}
+}
+\ No newline at end of file