--- a/graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/nodes/SLBinaryNode.java	Wed Jan 29 20:43:28 2014 -0800
+++ b/graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/nodes/SLBinaryNode.java	Wed Jan 29 20:45:43 2014 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2014, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -24,10 +24,11 @@
 
 import com.oracle.truffle.api.dsl.*;
 
+/**
+ * Utility base class for operations that take two arguments (per convention called "left" and
+ * "right). For concrete subclassses of this class, the Truffle DSL creates two child fields, and
+ * the necessary constructors and logic to set them.
+ */
 @NodeChildren({@NodeChild("leftNode"), @NodeChild("rightNode")})
 public abstract class SLBinaryNode extends SLExpressionNode {
-
-    public boolean isString(Object a, Object b) {
-        return a instanceof String || b instanceof String;
-    }
 }