Making Our Own Types and Typeclasses

Making Our Own Types and Typeclasses

1. Algebraic data types intro

   • data types
     • Bool
     • Int
     • Char
     • Maybe

2. Record syntax

   • Store information
     • data values
   • Getters and Setters
   • Status function

3. Type parameters

   • constructor
     • values parameters
     • produce new values
   • Values can arrays
   • Parameters containin more data
   • parameterized data
   • in Haskell to never add typeclass constraints in data declarations.

4. Derived instances

   • Typeclasses 101
     • typeclass
       • sort of an interface that defines some behavior
   • functions defined by the typeclasses
   • typeclasses
     • Eq
     • Ord
     • Enum
     • Bounded
     • Show
     • Read
     • just

5. Type synonyms

   • types are equivalent and interchangeable
   • giving some types different
   • distinction between type constructors and value constructors
     • Either
     • Maybe
     • Nothing

6. Recursive data structures

   • constructors have fields that are of the same type
     • recursive data types
   • constructor
     • cons
   • define functions as operators

7. Typeclasses 102

   • our own typeclasses
   • types instances of our typeclasses
   • cicles
     • for
     • where
       • Eq
   • instance keyword.
     • defining new typeclasses and instance
   • subclasses of other typeclasses

8. A yes-no typeclass

   • strictly using Bool
   • boolean semantics works
     • tells us for sure if it's true or not
   • takes one value

9. The Functor typeclass

   • things that can be mapped over
   • fmap
     • can hold
       • Int
       • Char
       • Bool
   • works only on lists
   • is just map
   • Types that can act like a box can be functors

10. Kinds and some type-foo

    • types are applied to type constructors
    • kinds
      • little labels
    • mapped the f over the first field