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