-ruleBaseIds (RuleBase ids _) = ids
-ruleBaseFVs (RuleBase _ fvs) = fvs
-
-emptyRuleBase = RuleBase emptyVarSet emptyVarSet
-
-addRuleBaseFVs :: RuleBase -> IdSet -> RuleBase
-addRuleBaseFVs (RuleBase rules fvs) extra_fvs
- = RuleBase rules (fvs `unionVarSet` extra_fvs)