27 struct Effect {  struct
33   Effect() : modality(DEFINITE) {}  in Effect()  argument
34   explicit Effect(Bounds b, Modality m = DEFINITE) : modality(m), bounds(b) {}  in modality()  argument
37   static Effect Unknown(Zone* zone) {  in Unknown()  argument
38     return Effect(Bounds::Unbounded(), POSSIBLE);  in Unknown()
41   static Effect Forget(Zone* zone) {  in Forget()  argument
42     return Effect(Bounds::Unbounded(), DEFINITE);  in Forget()
46   static Effect Seq(Effect e1, Effect e2, Zone* zone) {  in Seq()  argument
48     return Effect(Bounds::Either(e1.bounds, e2.bounds, zone), e1.modality);  in Seq()
52   static Effect Alt(Effect e1, Effect e2, Zone* zone) {  in Alt()  argument
53     return Effect(  in Alt()
81   Effect Lookup(Var var) {  in Lookup()
84         ? locator.value() : Effect::Unknown(Base::zone());  in Lookup()
88     Effect effect = Lookup(var);  in LookupBounds()
89     return effect.modality == Effect::DEFINITE  in LookupBounds()
94   void Seq(Var var, Effect effect) {  in Seq()
97       effect = Effect::Seq(locator.value(), effect, Base::zone());  in Seq()
108   void Alt(Var var, Effect effect) {  in Alt()
111       effect = Effect::Alt(locator.value(), effect, Base::zone());  in Alt()
126         Effect::Forget(Base::zone()), Effects(Base::zone()) };  in Forget()
136     void Call(Var var, Effect effect) { self.Seq(var, effect); }  in Call()
142     void Call(Var var, Effect effect) { self.Alt(var, effect); }  in Call()
148     void Call(Var var, Effect effect) {  in Call()
149       if (effect.modality == Effect::DEFINITE && !other.Contains(var)) {  in Call()
150         effect.modality = Effect::POSSIBLE;  in Call()
161     void Call(Var var, Effect effect) { effects.Seq(var, new_effect); }  in Call()
162     Effect new_effect;
187     typedef Effect Value;
189     static Effect NoValue() { return Effect(); }  in NoValue()