Programmer-Defined “Datatypes”

Use datatype to create an entirely new type -- one which could not be expressed using only the basic types, tuples, and lists.

datatype color = Red | Yellow | Green;

datatype color Green | Red | Yellow

val mycolor = Red;

val mycolor = Red : color

fun okToGo c = if c = Green then true else false;

val okToGo fn : color -> bool

okToGo(Red);

val it = false : bool

Previous slide

Next slide

Back to first slide

View graphic version