--- a/graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/nodes/local/SLReadLocalVariableNode.java	Thu Jan 30 17:52:24 2014 -0800
+++ b/graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/nodes/local/SLReadLocalVariableNode.java	Thu Jan 30 17:53:27 2014 -0800
@@ -26,10 +26,21 @@
 import com.oracle.truffle.api.frame.*;
 import com.oracle.truffle.sl.nodes.*;
 
+/**
+ * Node to read a local variable from a function's {@link VirtualFrame frame}. The Truffle frame API
+ * allows to store primitive values of all Java primitive types, and Object values. This means that
+ * all SL types that are objects are handled by the {@link #readObject} method. When a local
+ * variable changes its type, the frame access method throws an {@link FrameSlotTypeException},
+ * which causes not rewriting. The rewriting code is generated by the Truffle DSL.
+ */
 @PolymorphicLimit(1)
 @NodeField(name = "slot", type = FrameSlot.class)
 public abstract class SLReadLocalVariableNode extends SLExpressionNode {
 
+    /**
+     * Returns the descriptor of the accessed local variable. The implementation of this method is
+     * created by the Truffle DSL based on the {@link NodeField} annotation on the class.
+     */
     protected abstract FrameSlot getSlot();
 
     @Specialization(rewriteOn = {FrameSlotTypeException.class})