fact: Fixpoint lookup `{Eq a} {b} (dflt : b) (v : list (a * b)) (x : a) : b := match v with | nil => dflt | cons (k, v) xs => if k == x then v else lookup dflt xs x end.
imports: Hask.Ltac Hask.Control.Monad Hask.Data.Eq Hask.Data.Maybe Coq.Program.Wf Coq.Sorting.Sorted Coq.Classes.RelationClasses Coq.Lists.List