Quick notes on runtime stack frames

C-style approach
================

--------------
SP/FP
Parameters
Local variables
Return value
Saved registers
--------------

Lisp style
==========

--------------
SP/FP
Function ref ----->  Function representation as a list in the heap,
Saved registers        - function form (lambda, lambda-block, lambda-closure, lambda-block-closure)
--------------         - [ three environment lists ] 0 or 3
                       - [ function name ] 0 or 1
                       - parameter list
                       - [ statement ] 0 or more

Dynamic scope handling
----------------------
either (a) by searching the function's front environment list for an in-scope
           variable with the correct name
    or (b) by maintaining a global hash-table keyed on variable names,
           where the values are stacks of the current values of those variables
           (push on declaration, pop on leaving declaration scope)