QuickJS implementation

[dy]

Reference implementation of operator overloading by QuickJS:

class Vec2 {
        constructor(x, y) {
            this.x = x;
            this.y = y;
        }
}
    
    Vec2.prototype[Symbol.operatorSet] = Operators.create(
    {
        "+"(p1, p2) {
            var r = new Vec2();
            r.x = p1.x + p2.x;
            r.y = p1.y + p2.y;
            return r;
        },
        "-"(p1, p2) {
            var r = new Vec2();
            r.x = p1.x - p2.x;
            r.y = p1.y - p2.y;
            return r;
        },
        "=="(a, b) {
            return a.x == b.x && a.y == b.y;
        },
        "<"(a, b) {
            var r;
            /* lexicographic order */
            if (a.x == b.x)
                r = (a.y < b.y);
            else
                r = (a.x < b.x);
            return r;
        },
        "++"(a) {
            var r = new Vec2();
            r.x = a.x + 1;
            r.y = a.y + 1;
            return r;
        }
    },
    {
        left: Number,
        "*"(a, b) {
            return Vec2.mul_scalar(b, a);
        }
    },
    {
        right: Number,
        "*"(a, b) {
            return Vec2.mul_scalar(a, b);
        }
    });

    var a = new Vec2(1, 2);
    var b = new Vec2(3, 4);
    var r;

    r = a * 2 + 3 * b;
    assert(r.x === 11 && r.y === 16);
    assert(a == a, true);
    assert(a == b, false);
    assert(a != a, false);
    assert(a < b, true);
    assert(a <= b, true);
    assert(b < a, false);
    assert(b <= a, false);
    assert(a <= a, true);
    assert(a >= a, true);
    a++;
    assert(a.x === 2 && a.y === 3);
    r = ++a;
    assert(a.x === 3 && a.y === 4);
    assert(r === a);