Parameterizing over finite maps

Second attempt

• Corresponds to the following Haskell code:
  • class FiniteMap fm k | fm->k where
    empty :: v -> fm v
    lookup :: fm v -> k -> v
    update :: k -> v -> fm v -> fm v
• Problem: solved!
  • Implementations can impose restrictions on the key type:
    • instance Eq k => FiniteMap ((->) k) k where ...