Library Coq.micromega.VarMap

Require Import ZArith.
Require Import Coq.Arith.Max.
Require Import List.
Set Implicit Arguments.


Section MakeVarMap.
  Variable A : Type.
  Variable default : A.

  Inductive t : Type :=
  | Empty : t
  | Leaf : A -> t
  | Node : t -> A -> t -> t .

  Fixpoint find (vm : t) (p:positive) {struct vm} : A :=
    match vm with
      | Empty => default
      | Leaf i => i
      | Node l e r => match p with
                        | xH => e
                        | xO p => find l p
                        | xI p => find r p
                      end
    end.

End MakeVarMap.