"""Really ugly program to demonstrate the core idea of trampolines:

Trampolines are really event loops.
"""

from Tkinter import *

root = Tk()
textwidget = Text(root, height=40)
textwidget.pack()

DELAY = 30
N = 1000

def update_display(n, k):
    global textwidget
    textwidget.delete(1.0, END)
    textwidget.insert(END, "factorial(%s, %s)" % (n, k))

    
def do_factorial(n, k):
    update_display(n, k)
    if n != 0:
        root.after(DELAY, do_factorial, n-1, k*n)


root.after(DELAY, do_factorial, N, 1)
root.mainloop()