Operator functions

Kotlin allows us to provide implementations for a predefined set of operators with fixed symbolic representation (like \+ or \*) and fixed precedence. To implement an operator, we provide a member function or an extension function with a fixed name, for the corresponding type. Functions that overload operators need to be marked with the operator modifier:

data class IntListWrapper (val wrapped: List<Int>) {
    operator fun get(position: Int): Int = wrapped[position]
}

val a = IntListWrapper(listOf(1, 2, 3))
a[1] // == 2

More operator functions can be found in here