Lecture3

Lecture3 - Typeclasses

• Typeclasses

  • class
  • instance
  • {-# MINIMAL #-}

• Language extensions

  • {-# LANGUAGE InstanceSigs #-}

• Standard typeclasses

  • Eq, Ord, Show, Read, Num
  • deriving
  • {-# LANGUAGE GeneralizedNewtypeDeriving #-}

• Algebraic typeclasses

  • Semigroup
  • Monoid

• Kinds

• Functor

• Folds

  • foldr, foldl, foldl'
  • Foldable

• Strict and lazy evaluation

  • Lazy evaluation
  • Tail call optimization
  • Equational reasoning
  • {-# LANGUAGE BangPatterns #-}