exceptional

Essentially the Maybe type with error messages.

https://github.com/pharpend/exceptional

Version on this page:0.1.5.1@rev:1
LTS Haskell 14.27:0.3.0.0
Stackage Nightly 2019-09-21:0.3.0.0
Latest on Hackage:0.3.0.0

See all snapshots exceptional appears in

BSD-2-Clause licensed by Peter Harpending
Maintained by [email protected]
This version can be pinned in stack with:exceptional-0.1.5.1@sha256:a79514b512d8776f9ae66a80aeb3f604ac9ae1d4c5c98fdd9ea2acc8c312adda,2586

Module documentation for 0.1.5.1

Depends on 1 package(full list with versions):
base

exceptional

This is a Haskell library that exists to house a type:

data Exceptional x
  = Failure String
  | Success x

It’s much like Maybe, except instead of Nothing, we have Failure String.

A comparison could also be made to Either String. I made this library because I was dissatisfied with the Monad instance for Either. In this type, fail = Failure. It’s rather simple.

Installing

cabal install exceptional

Or, add exceptional to the build-depends field in your .cabal file.