On Sat, Oct 31, 2015 at 6:10 PM, Roel van Dijk <vandijk.roel@gmail.com> wrote:

Small nitpick, but I would generally put the "exception" or "error" in the Left part of an Either and a correct result in the Right part.

This has some advantages.
1 - Right is right as opposed to wrong. Easy to remember mnemonic.
2 - It fits neatly with the Monad (Either e) instance.

I think you're being modest when you call it a "small nitpick." If code can't get Left and Right right, that code immediately becomes very suspicious.

Thus, not

f2 :: Integer -> Either Integer ErrorString

but

f2 :: Integer -> Either ErrorString Integer

Nice catch.

-- Kim-Ee