Wonder why swap is not in the stdlib

# stdlib

[Eugen Martynov]

Wonder why swap is not in the stdlib

[Joffrey]

Could you please elaborate on the signature of the function and what it would do?

[Eugen Martynov]

swap(index1, index2)

[Eugen Martynov]

move item from index1 position to index2 and item from index2 to index1

[Eugen Martynov]

Ah oke, I was particularly thinking about swapping item in the ordered collection

[Eugen Martynov]

Oke, looks like not widely use case

[Eugen Martynov]

So anyone who needs - will just write three lines of code function

[Joffrey]

Ah I see. Thanks for clarifying. I don't know why it's not in there, but usually it means there is not a compelling reason to add it (the question is usually "why" rather than "why not"). Mutable collections are less common in general kotlin code than read-only collections, so that might be one part of the reason

[Eugen Martynov]

especially Kotlin promoting immutable data types

[ilya.gorbunov]

Sometimes swap is useful, mostly in advent-of-code type of tasks, but other than that we struggle to find compelling use cases. If you know some, drop a comment to https://youtrack.jetbrains.com/issue/KT-33768/Add-Collection.swap-extension-to-stdlib

[Derek Peirce]

I'd like the ability to write swap(::a, ::b) that swaps two `var`s, written using KProperty but compiled to completely eliminate that overhead and become just the standard temp-variable implementation.