Types and Typeclasses - Haskell

Types and Typeclasses - Haskell

1. Algebraic data types

   • data
     • Int
     • Bool
     • Char
     • Maybe
     • Example
       • data Shape
         • Circle
         • Rectangle
         • deriving
           • Show
             • printing results
       • data Point
         • Circle
           • Point
         • Rectangle
           • Point, Point
         • Show

2. Record Syntax

   • Person
     • String
     • String
     • Int
     • Float
     • String
     • with Record Syntax
       • firstName::String
       • lastName::String
       • age:: Int
       • height::Float
       • phoneNumber:: String
       • flavor::String

3. Type parameters

   • Constructor
     • data Maybe
       • Nothing
         • [Int]
         • [Char]
         • [[String]]
         • Car
           • a
             • company
           • b
             • model
           • c
             • year
         • Vector
           • a
           • a
           • a

4. Derived instances

   • Eq
   • Ord
   • Enum
   • Bounded
   • Show
   • Read

5. Type synonyms

   • [String]
     • [(String,String)]
       • [(Name, PhoneNumber)]
         • PhoneNumber = String
         • Name = String
   • [Char]

6. Recursive data structures

   • data List
     • Empty
     • Cons a (Lista a)
       • listHead
       • listTrail
     • infixr
       • *
       • +
       • ++
   • data Tree
     • singleton

7. Typeclasses 102

   • Eq
     • class Eq a where (==) :: a -> a -> Bool (/=) :: a -> a -> Bool x == y = not (x /= y) x /= y = not (x == y)
     • class Eq a where (==) :: a -> a -> Bool (/=) :: a -> a -> Bool x == y = not (x /= y) x /= y = not (x == y)

8. A yes-no typeclass

   • Bool
     • yesno::a
       • False
       • True

9. The Functor typeclass

   • Functor
     • fmap
       • Just X
       • Nothing
       • Right X
       • Left X

10. Kinds and some type-foo

    • :k