Data Types Questions and Answers#

types aka#

Types are also known as…

datatypes.

enumerate types#

List three datatypes that come with Prelude.

  • Char

  • Word

  • Double

values and types#

Values have types. In Haskell, we cannot have an untyped value. Types are like groups that contains values that belong to that group.

Enumerate a few values that would belong to the type (a.k.a datatype) Char and a few that would belong to the type Word.

  • Char:

    • 'a'

    • '9'

    • ' '

  • Word

    • 0

    • 42

It is important to note that Word includes only natural numbers, from zero onward.

data declarations#

What do data declarations do?

Data declarations define types (a.k.a. data types).

basic data declaration#

λ> :info Bool
data Bool = False | True

Identify type constructors and data constructors above.

Bool is the type constructor. False and True are the two possible data constructors that belong to the type or datatype Bool.

Note

Although we say data declaration, we are not defining __only__ data constructors. We are in fact defining both type constructors and data constructors.