'''
-=nero
Monday, May 08, 2011
'''
import sys
import re
import pprint
class StateMachineFoo(object):
'''
This is a template for a finite state machine that is dynamically built based
on the function names and docstring for the given functions
'''
def __init__(self):
self.init_sm()
self.state_trace = []
def init_sm(self):
# find all the states based on the regex
m = re.compile(r'_state.*',re.I)
# return a list of matches
state_names = filter(m.search,dir(self))
# get the function pointers to all of our states
state_ptrs = [getattr(self,state) for state in state_names]
# from the function pointers, suck up our dockstring and get our transitions
dictm = re.compile(r"{.*}",re.S)
state_trans = [eval(dictm.search(getattr(state, 'func_doc', '')).group(0)) for state in state_ptrs]
# use zip to create a tuple containing our state_name/state_transition pairings, and add
# them to the dictionary as key/value pairs
self.state_machine = dict(zip(state_names,state_trans))
def __str__(self):
return '\n'.join([
'\nSTATE_TRANS_DIAGRAM:',
'--------------------',
pprint.pformat(self.state_machine),
'\nSTATE_TRANSITION_TRACE:',
'-----------------------',
'\n'.join(self.state_trace),
])
def run(self, fname = '_state_start', announce = False):
'''
Enter into the state machine here. called run to
simply because it ties in w/ threading module
fname - override the beginning state
announce - print state name as you enter state
'''
self.state_trace = []
while 'None' != fname:
if announce:
print '\n\n %s' % fname.upper().center(60, '*')
self.state_trace.append(fname)
ret = getattr(self, fname)()
fname = self.state_machine[fname][ret]
def _state_start(self):
'''
{'SUCCESS': '_stateA', 'FAIL': '_state_stop'}
'''
return 'SUCCESS'
def _state_stop(self):
'''
{'SUCCESS': 'None', 'FAIL': 'None'}
'''
return 'SUCCESS'
def _stateA(self):
'''
{'SUCCESS': '_stateB','FAIL': '_error'}
'''
error = False
if error:
return 'FAIL'
else:
return 'SUCCESS'
def _stateB(self):
'''
{'SUCCESS': '_stateD','FAIL':'_error'}
'''
error = False
if error:
return 'FAIL'
else:
return 'SUCCESS'
def _stateC(self):
'''
{'SUCCESS': '_stateA','FAIL':'_error'}
'''
error = True
if error:
return 'FAIL'
else:
return 'SUCCESS'
def _stateD(self):
'''
{'SUCCESS': '_stateE','FAIL':'_error'}
'''
error = False
if error:
return 'FAIL'
else:
return 'SUCCESS'
def _stateE(self):
'''
{'SUCCESS': '_stateC','FAIL':'_error'}
'''
error = False
if error:
return 'FAIL'
else:
return 'SUCCESS'
def _error(self):
print "OH NO, AN ERROR!!! <EXITING>"
print self
sys.exit(-1)
if __name__ == '__main__':
# this is a really bad way to do this, probably want python argparse module, but for
# demo purposes, this should allow you to change your start state from the command line
# the simple/dirty way
sm = StateMachineFoo()
start_state = 'None'
if len(sys.argv) > 1:
start_state = sys.argv[1]
sm.run(start_state)
print sm
Diff to Previous Revision
--- revision 5 2011-09-30 05:15:51
+++ revision 6 2011-09-30 05:16:56
@@ -148,6 +148,11 @@
sys.exit(-1)
if __name__ == '__main__':
+
+ # this is a really bad way to do this, probably want python argparse module, but for
+ # demo purposes, this should allow you to change your start state from the command line
+ # the simple/dirty way
+
sm = StateMachineFoo()
start_state = 'None'
