stepThroughModel.py

import sys
import signal
import os
from ptyprocess import PtyProcessUnicode

# The purpose of this script is to serve as a wrapper around SPIN,
# providing functionality in interactive mode similar to stepping through
# an application, for instance in a MIPS emulator.
# See: http://spinroot.com/fluxbb/viewtopic.php?id=1662

p = PtyProcessUnicode.spawn(['spin', '-p', '-i', '-w', sys.argv[1]])

def no_real_input():
	line = p.readline()
	if ("Select [" in line):
		choice = input()
	print(line)

def handler(signum, frame):
    raise Exception("end of time")

while p.isalive():
	signal.signal(signal.SIGALRM, handler)
	signal.alarm(1)
	try:
	    no_real_input()
	except Exception as exc:
	    choice = input()
	    p.write(choice + "\n")