Making Our Own Types and Typeclasses

Making Our Own Types and Typeclasses

1. To define a new data type we use the word data

   • The part before the = is the Type and after the = are the value constructors: specify the values that the type can have
     • we can optionally add some types after it and those types define the values it will contain.
       • if there's only one value constructor, we can use the same name for the data type and the value constructor
         • We can export our data types. we just have to write it in the module declaration.
           • In parentheses, we specify the value constructor.
             • To add everything just put ( .. ) inside the parentheses.

2. RECORD SYNTAX

   • It’s an alternative to write data types.
     • We write the field types, and then write double colon :: to specify the type

3. Derived instances

   • Haskell can derive the behavior of these types to our data types.

4. Type synonyms

   • Give different names to the type data so that they make more sense to someone reading our code and documentation.

5. Recursive data structures

   • where one value of some type contains values of that type, which in turn contain more values of the same type and so on.

6. Binary search tree

   • An element points to two elements, one on its left and one on its right. The element to the left is smaller, the element to the right is bigger.

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