// Typed record literals and runtime type tags. Demonstrates is_a/is_type
// on record literals, type_of, and dispatching on a record's _type field
// rather than a sum type — records carry their own type name.

cell Shapes {
    face {
        signal circle(r: Int) -> Map
        signal square(s: Int) -> Map
        signal kind(shape: Map) -> String
        signal area(shape: Map) -> Int
        signal is_circle(shape: Map) -> Bool
    }

    on circle(r: Int)  { return Circle { r: r } }
    on square(s: Int)  { return Square { side: s } }

    on kind(shape: Map) {
        if is_a(shape, "Circle") { return "circle" }
        if is_a(shape, "Square") { return "square" }
        return "unknown"
    }

    // area uses the record tag to choose a formula (pi*r^2 truncated for circle)
    on area(shape: Map) {
        if is_a(shape, "Circle") { return floor(3.14159 * shape.r * shape.r) }
        if is_a(shape, "Square") { return shape.side * shape.side }
        return 0
    }

    on is_circle(shape: Map) {
        return is_type(shape, "Circle")
    }
}

cell test ShapesTest {
    rules {
        assert kind(circle(2)) == "circle"
        assert kind(square(3)) == "square"
        assert area(circle(2)) == 12
        assert area(square(4)) == 16
        assert is_circle(circle(1)) == true
        assert is_circle(square(1)) == false
        assert type_of(circle(1)) == "Map"
    }
}