state | Python Fiddle

#
# state machine
#

class State:

INITIAL   = 0
    YIELDING  = 1   # pseudo-state
    TERMINAL  = 2
    FIRSTUSER = 3

def __init__(self, id, on_entry, todo, on_exit, arcs):

self._id = id
        self._on_entry = on_entry
        self._todo = todo
        self._on_exit = exit
        self._arcs = arcs
  
    def on_entry( machine, context ):
        if self._on_entry:
            return self._on_entry( machine, context )
        else:
            return True
        
class Arc:
    def __init__(self, dest_id, trigger, guard, action):
        self._dest_id = dest_id
        self._trigger = trigger
        self._guard = guard
        self._action = action
        
class Event:
    def __init__(self):
        self._mask = Event.NULL
        
    def produce(self, mask):
        self._mask |= mask
        return self._mask
    
    def inspect(self, mask):
        return self._mask & mask
    
    def consume(self, mask):
        _mask = self._mask
        self._mask &= ~mask
        return _mask

Event.NULL       = 0x00000000
Event.ENTRY_FAIL = 0x01000000

class Machine:
    def __init__(self, states, context):
        self._states = states
        self._stack = []
        self._events = Event()
        self._cur_state = State.INITIAL
        self._context = context
        
    def run(self):
    	state = self._states[self._cur_state]
        
        while state != State.TERMINAL:
                        
            if not state.on_entry( self, context):
              	self._events.produce( Event.ENTRY_FAIL )
                    
                    
print( Event.NULL )
print( "0x%08x" % Event.ENTRY_FAIL )

Browser Version Not Supported

Due to Python Fiddle's reliance on advanced JavaScript techniques, older browsers might have problems running it correctly. Please download the latest version of your favourite browser.
Chrome 10+ Firefox 4+ Safari 5+
IE 10+

Let me try anyway!

Python Fiddle

Python Cloud IDE