Chapter 7. Making Our Own Types and Type Classes
So far, we’ve run into a lot of data types: Bool
,
Int
, Char
,
Maybe
, and so on. But how do we make our own? In
this chapter, you’ll learn how to create custom types and put them to work!
Defining a New Data Type
One way to make our own type is to use the data
keyword. Let’s see how the Bool
type is defined
in the standard library.
data Bool = False | True
Using the data
keyword like this means that a
new data type is being defined. The part before the equal sign denotes the type,
which in this case is Bool
. The parts after the equal sign are value constructors. They specify the different values that this ...
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