Parameterizing over finite maps

First attempt

• Corresponds to the following Haskell code:
  • class FiniteMap fm where
    empty :: v -> fm k v
    lookup :: fm k v -> k -> v
    update :: k -> v -> fm k v -> fm k v
• Problem: too general
  • No implementation can be completely polymorphic in the type of keys
• Also a reminder of the problem with type classes for container types in Haskell