On 2020-06-27 22:46 +0200, Marc Nieper-Wißkirchen wrote: > I have to think of how much `-and' and `-or' without any argument make > sense logically. In any case, the payload of the Just/Right or the > Left would have nothing to do with truth or the falsehood of the > `-and' or `-or' form. So wrapping `#t' or `#f' is definitely not "the > right thing". This seems like the stickiest point to get right with these forms. I'd tentatively suggest the following. If no expressions are passed to the maybe/either -and/-or forms, * maybe-or returns Nothing * maybe-and returns a Just whose payload is a single unspecified value * either-or returns a Left whose payload is a single unspecified value * either-and returns a Right whose payload is a single unspecified value For the last three forms: I find the container-of-no-values solution elegant, but I think single-valued containers are much easier to deal with (as John also notes). The unit of the operations are, respectively, any Just/Left/Right, so it makes sense to me that we leave the payload unspecified. -- Wolfgang Corcoran-Mathe <xxxxxx@sigwinch.xyz> "Earth is the cradle of the mind, but one cannot live in a cradle forever." --Konstantin Tsiolkovsky
