2094         nullable = {}
2099                     nullable[p.name] = 1
2102                     if not t in nullable: break
2104                     nullable[p.name] = 1
2105            if len(nullable) == num_nullable: break
2106            num_nullable = len(nullable)
2107         return nullable
2140     def dr_relation(self,C,trans,nullable):  argument
2207     def compute_lookback_includes(self,C,trans,nullable):  argument
2242                                 if not p.prod[li] in nullable: break
2281     def compute_read_sets(self,C, ntrans, nullable):  argument
2282         FP = lambda x: self.dr_relation(C,x,nullable)
2283         R =  lambda x: self.reads_relation(C,x,nullable)
2340         nullable = self.compute_nullable_nonterminals()
2346         readsets = self.compute_read_sets(C,trans,nullable)
2349         lookd, included = self.compute_lookback_includes(C,trans,nullable)