Part 3 is done! Defined a Var class to hold variable info, and a stack-of-lists to represent blocks and their variables. Started on part 4, but its silly. Part 3 says to use a stack, popping blocks off once theyre finished, but part 4 asks you to save all information about every variable. This will require some new data stuctures -- possible a list of block pointers, identical to the block stack but without pop after each block is finished?