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An /r/haskell thread made me realize Hackett has an opportunity to avoid the mess that led to ExceptT in Haskell, but I don’t actually know which name for the transformer is the best. In an ideal world, what do you all think would be ideal?

EitherT
63.6%
ErrorT
22%
ExceptT
14.4%

118 votesFinal results

Brendan Zabarauskas

@brendanzab

Replying to

@lexi_lambda

Don't call it `Either`, call it `data Result e a = Ok a | Err e` (like in Elm and Rust), and call the transformer `ResultT`.

3:43 AM · Nov 21, 2017Twitter Web Client

Replying to

and

Do NOT do this. It's an anti-pattern: it assumes the side you bind on is an "okay" result and the other is an error, which is not always the case.

berdario

@berdari0

Nov 21, 2017

The opposite can also be seen as an antipattern: Result is a Functor, but Either shouldn't be (Result could be a newtype wrapper around Either, though). If needed a different newtype wrapper could have a left biased Functor instance as well

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