ye

# arrow

[pakoito]

ye

[Chris Paul]

i'll reply here to keep noise down

[Chris Paul]

mapLeft allows me to do some conditional mapping on error, i need a flatMapLeft

[Chris Paul]

hmm

[Chris Paul]

i'd have a mapLeft, then it.flip().flatMap { callEitherMethod(it) }.flip() ?

[kioba]

I think what Pakoito suggest is that you can write your own flatMapLeft by

fun Either<L, R>.flatMapLeft(...) =
this.flip().flatMap(…).flip()

[Chris Paul]

hmm

[Chris Paul]

i thik it would have to exist within a mapLeft so that it is only invoked when it should be

[kioba]

in case of Right value the flatMapLeft only does 2x flipping

[Chris Paul]

hmm

[Chris Paul]

of course

[Chris Paul]

that is clever

[Chris Paul]

thanks