2096         nullable = {}
2101                     nullable[p.name] = 1
2104                     if not t in nullable: break
2106                     nullable[p.name] = 1
2107            if len(nullable) == num_nullable: break
2108            num_nullable = len(nullable)
2109         return nullable
2142     def dr_relation(self,C,trans,nullable):  argument
2209     def compute_lookback_includes(self,C,trans,nullable):  argument
2244                                 if not p.prod[li] in nullable: break
2283     def compute_read_sets(self,C, ntrans, nullable):  argument
2284         FP = lambda x: self.dr_relation(C,x,nullable)
2285         R =  lambda x: self.reads_relation(C,x,nullable)
2342         nullable = self.compute_nullable_nonterminals()
2348         readsets = self.compute_read_sets(C,trans,nullable)
2351         lookd, included = self.compute_lookback_includes(C,trans,nullable)