But you still can't use

kotlin.Result

as return type...

@uhe what was the reasoning behind that restriction ?

@suresh https://github.com/Kotlin/KEEP/blob/master/proposals/stdlib/result.md#limitations

i've started using Either in one project and i quite like that you can effectively throw an exception without the performance penalty, instead of

throw PEBKACError())

, it 's now just

Either.left(PEBKACError())

Optics is the next Arrow feature i'm slowly adding to this project

@janvladimirmostert if you dont need stacktraces - disable them:

class FastException: Exception() { override fun fillInStackTrace() = null }

and 99.5% of performance penalty is magically gone. In many cases throwing such exception will perform almost like GOTO

oh wow