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Calling Crux an "Object Oriented" programming language is going a bit too far. It's more diplomatic to say it's an "Object Having" language.

Objects in Crux map to bare JS objects.

Object types are row polymorphic, which means that the type is comprised of a set of name/type pairs that the object provides. Another term for this is "structural typing."

Object types are enclosed in curly braces.

type Point = {
    x: Number,
    y: Number,

(the final comma is optional)

The . operator is used to access a property of an object.

fun length(point) {
    sqrt(point.x * point.x + point.y + point.y)

Objects can be created with the same syntax you see in JS:

let mypoint = {
    x: 5,
    y: 2,

Again, the final comma is optional.

Row-polymorphism says that a function is typed according to its fields and their types. The following is thus valid:

let point_one = { x : 5, y : 2 };
let named_point_two = { name : "The best point", x : 9, y : 3 }
fun distance(p1, p2) {
    let dx = p1.x - p2.x
    let dy = p1.y - p2.y
    sqrt(dx * dx + dy * dy)
print(distance(point_one, named_point_two))

In this example, the distance function can accept either point, because both are compatible with the type {x:Number, y:Number}.