Here’s an example that uses Lumpy to generate a stack diagram. You can download it from http://thinkpython.com/code/lumpy_demo2.py.
from swampy.Lumpy import Lumpy def countdown(n): if n <= 0: print 'Blastoff!' lumpy.object_diagram() else: print n countdown(n-1) lumpy = Lumpy() lumpy.make_reference() countdown(3)
Figure 22.2.1 shows the result. Each frame is represented with a box that has the function’s name outside and variables inside. Since this function is recursive, there is one frame for each level of recursion.
Remember that a stack diagram shows the state of the program at a particular point in its execution. To get the diagram you want, sometimes you have to think about where to invoke
In this case I invoke
object_diagram after executing the base case of the recursion; that way the stack diagram shows each level of the recursion. You can call
object_diagram more than once to get a series of snapshots of the program’s execution.