local-state(f;base;X;e)
== if e  X then f(prior-state(f;base;X;e),X(e)) else prior-state(f;base;X;e) fi  

latex

---

clarification:

es-interface-local-state{i:l}
es-interface-local-state(es; f; base; X; e)
== if e  X
== then f(es-local-prior-state{i:l}(es; f; base; X; e),X(e))
== else es-local-prior-state{i:l}
== else es-local-prior-state(es; f; base; X; e)
== fi  

latex

Definitions	prior-state(f;base;X;e), X(e), f(a), e  X, if b then t else f fi
FDL editor aliases	es-interface-local-state