How to explain implementation in Kotlin

[esmeraude es]

I am really new in Kotlin programming language. I work with generic types and I found code statements shown below. What does it mean? What is the meaning of each line?

class s(val b: t) : t by b {
    fun f1(): Int = b.f3 + 1
    override fun f2(g: Int): Any? = when {
        g == 0 -> null
        else -> b.f2(g - 1)
    }
    override fun l(g: Int, h: k?, z: m):
            k = when {
        g == 0 -> z.f1.f2.f3(1, z, true)
        else -> b.l(g - 1, h, z)}}
    override fun f4 (g: Int): Short = when {
        g == 0 -> 0
        else -> b.f4(g - 1)}}}

[Tim Moores]

That seems deliberately written to obscure its intent. But without knowing what the involved objects are, it makes even less sense to try and decipher it. Have you asked the person you got this from?