Update WORKLOG.md

WORKLOG.md

@@ -6,7 +6,7 @@
 
 ## Challenges:
  -  Nested structures were a challenge. A function inside a function/class needs us to build correct scoping as well as dealing with dependencies.
-    -  This is dealt by the class:StackVarRuntimeInfo and function:getStackVar.
+    -  This is dealt by the class:StackVarRuntimeInfo and function:getStackVar. Static links were maintained in the call stack for each function to access stack frames of previous function.
  -  Handling Strings was difficult as storage and access was more complex than lists.
     -  In order for us to easily determine the correctness, we intentionally matches the error messages to the reference implementation.
  -  Creation and use of objects was a major challenge.