Kotlin - Override/Implement array-like accessor function

Is it possible to override or implement the `[]` accessors in Kotlin (using operator overloading or similar)?

<!-- language: kotlin -->

val testObject = MyCustumObject()
println(testObject["hi"]) // i.e. implement this accessor.


In Python this is possible by implementing `__getitem__` and `__setitem__`.

You have to override get().

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a[i] translates to a.get(i)

As stated in [the documentation](

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) the `a[i]` is translated to `a.get(i)`. In example:

class MyObject {
operator fun get(ix:Int):String{
return "hello $ix"
}
}

Let's you write:

val a = MyObject()
println(a[123]) //-> "hello 123"

Similarly `a[i] = b` is translated to a method call `a.set(i, b)`.

In Kotlin, it is [`get` and `set` operator functions](

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) that you need to implement:

class C {
operator fun get(s: String, x: Int) = s + x
operator fun set(x: Int, y: Int, value: String) {
println("Putting $value at [$x, $y]")
}
}

And the usage:

val c = C()
val a = c["123", 4] // "1234"
c[1, 2] = "abc" // Putting abc at [1, 2]



You can define `get` and `set` with arbitrary number of parameters for *indices* (at least one, of course); in addition, `set` has the expression which is assigned at the use site passed as its last argument:

* `a[i_1, ..., i_n]` is translated to `a.get(i_1, ..., i_n)`

* `a[i_1, ..., i_n] = b` is translated to `a.set(i_1, ..., i_n, b)`

`get` and `set` can have different overloads as well, for example:

class MyOrderedMap<K, V> {
// ...

operator fun get(index: Int): Pair<K, V> = ... // i-th added mapping
operator fun get(key: K): V = ... // value by key
}
<sup>Note: this example introduces undesirable ambiguity for `MyOrderedMap<Int, SomeType>` since both `get` functions will match calls like `m[1]`.</sup>