// Sample: Operator Overloading in Lyng

class Vector(val x, val y) {
    // Overload +
    fun plus(other) = Vector(x + other.x, y + other.y)
    
    // Overload -
    fun minus(other) = Vector(x - other.x, y - other.y)
    
    // Overload unary -
    fun negate() = Vector(-x, -y)
    
    // Overload ==
    fun equals(other) {
        if (other is Vector) x == other.x && y == other.y
        else false
    }
    
    // Overload * (scalar multiplication)
    fun mul(scalar) = Vector(x * scalar, y * scalar)
    
    override fun toString() = "Vector(${x}, ${y})"
}

val v1 = Vector(10, 20)
val v2 = Vector(5, 5)

println("v1: " + v1)
println("v2: " + v2)

// Test binary +
val v3 = v1 + v2
println("v1 + v2 = " + v3)
assertEquals(Vector(15, 25), v3)

// Test unary -
val v4 = -v1
println("-v1 = " + v4)
assertEquals(Vector(-10, -20), v4)

// Test scalar multiplication
val v5 = v1 * 2
println("v1 * 2 = " + v5)
assertEquals(Vector(20, 40), v5)

// Test += (falls back to plus)
var v6 = Vector(1, 1)
v6 += Vector(2, 2)
println("v6 += (2,2) -> " + v6)
assertEquals(Vector(3, 3), v6)

// Test in-place mutation with plusAssign
class Counter(var count) {
    fun plusAssign(n) {
        count = count + n
    }
}

val c = Counter(0)
c += 10
c += 5
println("Counter: " + c.count)
assertEquals(15, c.count)