A map reduce based product currying

map_reduce.scala

object exercise {
    def mapReduce(
        func: Int=>Int, combine: (Int, Int) => Int, zero: Int
        )(a: Int, b: Int):  Int = {
            if (a > b) zero
            else combine(
                func(a),
                mapReduce(func, combine, zero)(a + 1, b)
            )
    }

    def product(f: Int => Int)(a: Int, b: Int): Int = {
        mapReduce(f, (x, y) => x * y, 1)(a, b)
    }


    def main(args: Array[String]): Unit = {
        println(product(x => x * x)(3, 4))
    }
}