without looking at the docs, guess what this does:...

# advent-of-code

[Michael de Kaste]

without looking at the docs, guess what this does:

val packetVersion = stringbuilder.removeRange(0..2).toLong(2)

I guessed wrong this morning 😉

[elizarov]

Did you want to do substring?

[Michael de Kaste]

No, I expected that removeRange(0..2) on a stringbuilder, removes those elements from that stringbuilder and then returns them.
instead, removeRange on a stringbuilder creates a whole new stringbuilder with everything but the chars at that range.

[elizarov]

I see. That’s a rough part of Kotlin APIs, indeed, when you work with mutable types.

[Michael de Kaste]

but that could just be me on a very early morning though 🧐

[Michael de Kaste]

was used to the removeFirst-esque functions of mutable collections and thought removeRange worked the same, since stringbuilder is a mutablestring

[Michael de Kaste]

should I make a youtrack with removeAtRange ? 👀

[elizarov]

It’s not the only inconsistently named function when you look at mutable/immutable things in stdlib. Consistently cleaning up the naming at this point maybe already too late, but there’s a chance we can fix most of those in a different way by proper IDE inspections and/or compiler warnings. However, I don’t see a good solution for this particular case of removeRange. Moreover, there’s a whole family of those extensions on `CharSequence`: removePrefix, removeSuffix, removeSurrounding that return a new CharSequence just like removeRange, which makes them confusing when applied to StringBuilder. because you might expect them to work similarly to `removeFirst`/`removeLast`/`removeAll`/etc on mutable lists.

[ephemient]

the difference between CharSequence and StringBuilder functions has bitten me before too. I also don't see much that can be done about it, though.

[Michael de Kaste]

I think one of the namings could be excludeRange excludePrefix, etc. and then rewrite the removes, but that seems like hindsight.

but removeAtRange(...) doesn't exist on any mutable collection, which could technically still be added for all of them

[Michael de Kaste]

or removeInRange if that sounds better

[Jacob]

Or copy off ruby and make it removeRange! 😛