decorated.py

def runsimulation(f):
    def checkrun():
        if len(changestate) >= 3 and changestate[-3] == changestate[-1]:
            m("stuck in loop")
        elif not len(changestate) or changestate[-1]:
            f()
        else:
            m(len(changestate), " state changes - finished.")
    return checkrun

@runsimulation
def simulate():
    for square in grid:
        if amialive(square):
            grid[square] = (grid[square][0], 1)
        else:
            grid[square] = (grid[square][0], 0)
        box = Box(square)
        changecolor(box, n=1)
    changestate.append([])
    for square in grid:
        if grid[square][0] != grid[square][1]:
            changestate[-1].append(square)
        grid[square] = (grid[square][1], 0)