## Creature Project
## CSC323: Group 1: Nora, Terian, Josh, and Jordan
## 4/7/10
## LogicPredicate.py: Checks and/or/not.
###Borrowed code from Group 0

from Predicate import *

class AndPredicate(LogicPredicate):
    '''performs an n-way boolean AND on the list of predicates'''
    def holds(self, world, location):
        for predicate in self.predicateList
            if not predicate.holds(world, location):
                return False
        return True
    
    def __str__(self):
    	return ''.join("(AND ",' '.join((pl.__str__() for pl in \
    	 self.predicateList)), ")")

class OrPredicate(LogicPredicate):
    '''performs an n-way boolean OR on the list of predicates'''
    def holds(self, world, location):
        for predicate in self.PredicateList
            if predicate.holds(world, location):
                return True
        return False
        
    def __str__(self):
    	return ''.join("(OR",' '.join((pl.__str__() for pl in \
    	 self.predicateList)), " )")	
        
class NotPredicate(LogicPredicate):
    '''inverts the result of its child predicate'''
    def __init__(self, pred):
        self.Predicate = pred
    def holds(self, world, location):
        return not self.Predicate.holds(world, location)
    def __str__(self):   
		return ''.join("(NOT ", self.Predicate.__str__(), " )")