from-sum
Combinators for working with Maybe and Either
https://github.com/cdepillabout/from-sum
| LTS Haskell 24.16: | 0.2.3.0 |
| Stackage Nightly 2025-10-24: | 0.2.3.0 |
| Latest on Hackage: | 0.2.3.0 |
Maintained by [email protected]
This version can be pinned in stack with:
from-sum-0.2.3.0@sha256:b2c64e1e2073f6cfb9b69a6205606042d9dcb3b2742a7d598f574ba62f5de4ad,1321Module documentation for 0.2.3.0
- Control
Depends on 2 packages(full list with versions):
Used by 1 package in lts-19.19(full list with versions):
Control.FromSum
This Haskell module exports the fromEitherM and fromMaybeM convenience
functions.
fromMaybeM :: m a -> Maybe a -> m a
fromEitherM :: (e -> m a) -> Either e a -> m a
fromEitherM leftAction eitherValue is the same as either leftAction pure eitherValue.
fromMaybeM nothingAction maybeValue is the same as maybe nothingAction pure maybeValue.
Usage
>>> import Control.FromSum (fromEitherM, fromMaybeM)
>>> fromMaybeM [] $ Just 5
[5]
>>> fromMaybeM [] Nothing
[]
>>> fromEitherM (\s -> [length s]) $ Right 5
[5]
>>> fromEitherM (\s -> [length s]) $ Left "foo"
[3]