Bug fix: looking up and modifying variables in the local stack was not being done properly, now it works. Before this fix, only the most recently pushed namespace was being looked-up or modified. Now the whole namspace is looked up and the correct variable in the correct namespace is being modified. If all namespaces on the stack do not have the variable then lookup fails, and if update should insert a value the value is inserted in the top-most namespace on the stack.