action.py

class Action(object):
  """
  The action class is used to define operators.
  Each action has a list of preconditions, an "add list" of positive effects,
  a "delete list" for negative effects, and the name of the action.
  The lists for preconditions and effects are lists of Proposition objects.
  Two actions are considered equal if they have the same name.
  """
  
  def __init__(self, name, pre, add, delete, isNoOp = False):
    """
    Constructor
    """
    self.pre = pre  	    # list of the precondition propositions 
    self.add = add 		    # list of the propositions that will be added after applying the action    
    self.delete = delete  # list of the propositions that will be deleted after applying the action    
    self.name = name 	    # the name of the action as string
    self.noOp = isNoOp 	  # true if the action is a noOp
    
  def getPre(self):
    return self.pre
  
  def getAdd(self):
    return self.add
  
  def getDelete(self):
    return self.delete
  
  def getName(self):
    return self.name
  
  def isPreCond(self, prop):
    return prop in self.pre
  
  
  def isPosEffect(self, prop): 
    """
    True if the proposition prop is a positive effect of the action
    """
    return prop in self.add
  
  def isNegEffect(self, prop):
    """
    Returns true if the proposition prop is a negative effect of the action 
    """
    return prop in self.delete

  def allPrecondsInList(self, propositions):
    """
    Returns true if all the precondition of the action
    are in the propositions list
    """
    for pre in self.pre:
      if pre not in propositions:
        return False
    return True
    
  def isNoOp(self):
    """
    Returns true if the action in noOp action
    """
    return self.noOp
  
  def __eq__(self, other):
    return (isinstance(other, self.__class__)
      and self.name == other.name)

  def __str__(self):
    return self.name
  
  def __ne__(self, other):
    return not self.__eq__(other)
    
  def __lt__(self, other):
    return self.name < other.name