Can someone explain the differences between `Opti...

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[Fred Friis]

Can someone explain the differences between

Option.else vs Option.getOrElse

and

Either.filterOrElse vs Either.filterOrOther

[Imran/Malic]

which version are you running?

[Fred Friis]

0.9.0

[Fred Friis]

is that bad 😬

[Imran/Malic]

no not at all

[simon.vergauwen]

@Fred Friis if you check the signature it should be like.

fun <A> Option<A>.else(f: () -> Option<A>): Option<A>
fun <A> Option<A>.getOrElse(f: () -> A): A

So getOrElse works similar to ?: but instead of going from A? -> A you go from Option<A> to A.

else works similarly but it doesn’t unwrap, so the result remains wrapped within Option. Similar to null ?: null, which is not allowed with getOrElse.

So while ?: can deal with more different situations the return type depends on the argument, which is not the case with else or getOrElse.

[simon.vergauwen]

Oh you already got an other answer… 😅

[Fred Friis]

@simon.vergauwen still much appreciated!

[Mike]

Either.filterOrElse and Either.filterOrOther are the same under the covers except for one aspect.

If the predicate is false, both call default. filterOrElse does not pass anything whereas filterOrOther passes the value of the Either.

I added this as I was using filtering for error handling, and wanted to include information about the filtered out value in my errors. filterOrOther allows it to flow nicely, where filterOrElse required having the variable available somewhere in the more general scope.