NormalCompose.kt

typealias StringPair = Pair<String, String>
typealias IntPair = Pair<Int, Int>

//this is prone to exception if str isn't in the right format e.g., "1, 2, 3, 4, 5"
val split: (String) -> Pair<StringPair, StringPair> = { str ->
    val (a, b, c, d) = str.split(",")
    Pair(Pair(a, b), Pair(c, d))
}

val convertToInt: (pair: Pair<StringPair, StringPair>) -> Pair<IntPair, IntPair> = { pair ->
    Pair(Pair(pair.first.first.toInt(), pair.first.second.toInt()),
            Pair(pair.second.first.toInt(), pair.second.second.toInt()))
}

val transform: (pair: Pair<IntPair, IntPair>) -> Int = { pair ->
    (pair.first.first + pair.first.second)/(pair.second.first + pair.second.second)
}

fun <A,B,C>combine(f: (B) -> C, g: (A) ->B): (A) -> C {
    return { x -> f(g(x)) }
}

val result = combine(combine(transform, convertToInt), split)