[Haskell-cafe] testing for exceptions

Kim-Ee Yeoh ky3 at atamo.com
Mon Nov 2 02:38:09 UTC 2015

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

> 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

Thus, not

  f2 :: Integer -> Either Integer ErrorString


  f2 :: Integer -> Either ErrorString Integer
Nice catch.

-- Kim-Ee
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