In Kotlin you can do something like this:
val s: String = "Hey"
println(s[1])
or simply:
println("Hey"[1])
and you will print e.
But what if you want to extend this behavior to your own classes? What interface do you need to implement to accomplish this syntax?
I looked at String's supertypes and only found Comparable<String> and CharSequence, neither of which had any other supertypes themselves, so my quest ended early.
For example in Python, by defining a method called __getitem__ in a class, you can bestow the objects of that class the ability to be used with square brackets syntax like this a[i]; I was wondering how this was possible in Kotlin.
Thanks in advance.
You can use Kotlin's operator overloading, specifically the overloading for indexed access operators.
The syntax "Hey"[1] is just an alias for "Hey".get(1) (if not on the left-hand side of an assignment, where it would be an alias for "Hey".set(1, ...)).
Apparently just having a method get(i: Int) suffices. Interesting...