# Pastebin 5HfiyWTt
class SomeTE: TileEntity(/* etc */) {
    val nbtData: NBTTagCompound = NBTTagCompound()
    val someProp: MutableList<String> by nbtData
        
    // Save/Load nbtData in the relevent hooks.
    // Now you can access someProp as a normal property, except the magick below will transparently read/write it from nbtData at runtime.
}
    
// WARNING: MAgick:

inline operator fun <reified T> NBTTagCompound.getValue(thisRef: Any?, prop: KProperty<*>): T {
    when(T::class) {
        Int::class -> return getInteger(prop.name) as T
        String::class -> return getString(prop.name) as T
        MutableList::class -> {
            when (T::class.typeParameters[0]) {
                String::class -> {
                    var list = getTag(prop.name) as NBTTagList

                    return (MutableList<String>(list.tagCount()) {
                        it: Int -> list.getStringTagAt(it)
                    }) as T
                }
            }
        }
    }

    throw InvalidArgument("Butts butts butts.")
}

inline operator fun <reified T>  NBTTagCompound.setValue(thisRef: Any?, prop: KProperty<*>, value: T) {
    when(T::class) {
        Int::class -> setInteger(prop.name, value as Int)
        String::class -> setString(prop.name, value as String)
        MutableList::class -> {
            when(T::class.typeParameters[0]) {
                String::class -> {
                    var list = NBTTagList()

                    (value as MutableList<String>).forEach {
                        list.appendTag(NBTTagString(it))
                    }

                    setTag(prop.name, list)
                }
            }
        }
    }
}