class Node:
"""A state of an NFA or DFA."""
def __init__(self):
# Preinitialise the list of empty transitions, because
# the nfa-to-dfa algorithm needs it
#self.transitions = {'':[]}
self.transitions = TransitionMap()
self.action = None # Action
self.number = 0 # for debug output
self.action_priority = LOWEST_PRIORITY
self.epsilon_closure = None # used by nfa_to_dfa()
def destroy(self):
#print "Destroying", self ###
self.transitions = None
self.action = None
self.epsilon_closure = None
def add_transition(self, event, new_state):
self.transitions.add(event, new_state)
def link_to(self, state):
"""Add an epsilon-move from this state to another state."""
self.add_transition('', state)
def set_action(self, action, priority):
"""Make this an accepting state with the given action. If
there is already an action, choose the action with highest
priority."""
if priority > self.action_priority:
self.action = action
self.action_priority = priority
def get_action(self):
return self.action
def get_action_priority(self):
return self.action_priority
def is_accepting(self):
return self.action is not None
def __str__(self):
return "State %d" % self.number
def dump(self, file):
# Header
file.write(" State %d:\n" % self.number)
# Transitions
#self.dump_transitions(file)
self.transitions.dump(file)
# Action
action = self.action
priority = self.action_priority
if action is not None:
file.write(" %s [priority %d]\n" % (action, priority))
def __init__(self):
# Preinitialise the list of empty transitions, because
# the nfa-to-dfa algorithm needs it
#self.transitions = {'':[]}
self.transitions = TransitionMap()
self.action = None # Action
self.number = 0 # for debug output
self.action_priority = LOWEST_PRIORITY
self.epsilon_closure = None # used by nfa_to_dfa()