A composite type, also called tuple, or record, is a type made of many types. You could see that as a vector in mathematics. This is useful because a function may only return one value, so you can wrap many values inside a tuple using this. You will also use this when creating new types.
let person = ("name", 5);;
You can create a composite type, also called tuple (or record). When the type is made of two types, we are calling it a couple.
let person = ("name", 5) (* same, but that's not readable 🙄 *) let person = "name", 5
The type is
string * int.
Extract values from a couple
When the tuple is made of two types, we are calling it a couple. You got the functions
fst (first) and
snd (second), to extract its values.
let name = fst person (* "name" *) let age = snd person (* 5 *)
Extract values from a tuple
let (name, age) = person let (name, _) = person (* name only *) let (_, age) = person (* age only *)