Rename OpNode to BinaryInfixNode.

src/org/nwapw/abacus/tree/BinaryInfixNode.java

@@ -3,7 +3,7 @@ package org.nwapw.abacus.tree;
 /**
  * A tree node that represents an operation being applied to two operands.
  */
-public class OpNode extends TreeNode {
+public class BinaryInfixNode extends TreeNode {
 
     /**
      * The operation being applied.
@@ -18,14 +18,14 @@ public class OpNode extends TreeNode {
      */
     private TreeNode right;
 
-    private OpNode() {}
+    private BinaryInfixNode() {}
 
     /**
      * Creates a new operation node with the given operation
      * and no child nodes.
      * @param operation the operation.
      */
-    public OpNode(String operation){
+    public BinaryInfixNode(String operation){
         this(operation, null, null);
     }
 
@@ -36,7 +36,7 @@ public class OpNode extends TreeNode {
      * @param left the left node of the expression.
      * @param right the right node of the expression.
      */
-    public OpNode(String operation, TreeNode left, TreeNode right){
+    public BinaryInfixNode(String operation, TreeNode left, TreeNode right){
         this.operation = operation;
         this.left = left;
         this.right = right;

src/org/nwapw/abacus/tree/NumberReducer.java

@@ -27,10 +27,10 @@ public class NumberReducer implements Reducer<NumberInterface> {
     public NumberInterface reduceNode(TreeNode node, Object... children) {
         if(node instanceof NumberNode) {
             return ((NumberNode) node).getNumber();
-        } else if(node instanceof OpNode){
+        } else if(node instanceof BinaryInfixNode){
             NumberInterface left = (NumberInterface) children[0];
             NumberInterface right = (NumberInterface) children[1];
-            Function function = manager.operatorFor(((OpNode) node).getOperation()).getFunction();
+            Function function = manager.operatorFor(((BinaryInfixNode) node).getOperation()).getFunction();
             if(function == null) return null;
             return function.apply(left, right);
         } else if(node instanceof UnaryPrefixNode) {

src/org/nwapw/abacus/tree/TreeBuilder.java

@@ -163,7 +163,7 @@ public class TreeBuilder {
                 TreeNode right = fromStringRecursive(source, matches);
                 TreeNode left = fromStringRecursive(source, matches);
                 if(left == null || right == null) return null;
-                else return new OpNode(operator, left, right);
+                else return new BinaryInfixNode(operator, left, right);
             } else {
                 TreeNode applyTo = fromStringRecursive(source, matches);
                 if(applyTo == null) return null;