Hackage :: [Package]

exceptional: Essentially the Maybe type with error messages.

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This is a very simple 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.

Changes

0.3.0.0
Fix erroneous behavior in foldExceptional function added in version 0.2. This release actually does break (or rather fix) the foldExceptional function, so be careful.
0.2.0.0
Add exceptional function to encapsulate ordinary exceptions in the Exceptional monad. Add folding functions.

This release does not actually break the API, however I was rather tired when I chose the version number. This should be 0.1.6.

0.1.5.0
Add exceptIO function to encapsulate IO errors in the Exceptional monad.
0.1.4.3
Fix bug where exceptional won't compile on base < 4.8. Also move the changelog back to the description so it's more visible.
0.1.4.2
Moved change log to a separate file so Hackage displays it correctly.
0.1.4.1
Documentation enhancements/fixes.
0.1.4.0
Added fromMaybe and toMaybe functions, and a link to the bug tracker.
0.1.3.0
Fixed a typo. 0.1.2.0 won't build. Also added definition of empty for Alternative.
0.1.2.0
Added fromEither and toEither functions.
0.1.1.3
Hackage is terrible. Yet another formatting fix.
0.1.1.2
Yet another formatting fix.
0.1.1.1
Formatting fix to the haddock documentation.
0.1.1.0
Add runExceptional function.
0.1.0.1
Minor documentation changes. No changes to the API.
0.1.0.0
Initial version
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Versions [RSS] 0.1.0.0, 0.1.0.1, 0.1.1.0, 0.1.1.1, 0.1.1.2, 0.1.1.3, 0.1.2.0, 0.1.3.0, 0.1.4.0, 0.1.4.1, 0.1.4.2, 0.1.4.3, 0.1.5.1, 0.2.0.0, 0.3.0.0 (info)
Dependencies base (>=4 && <5), exceptions [details]
License BSD-2-Clause
Copyright Copyright (c) 2015, Peter Harpending.
Author Peter Harpending
Maintainer peter@harpending.org
Uploaded by pharpend at 2015-07-22T22:58:59Z
Category Control
Home page https://github.com/
Bug tracker https://github.com/pharpend/exceptional/issues
Source repo head: git clone https://github.com/pharpend/exceptional.git -b master
this: git clone https://github.com/pharpend/exceptional.git -b master(tag 0.3.0.0)
Reverse Dependencies 1 direct, 0 indirect [details]
Downloads 11503 total (73 in the last 30 days)
Rating (no votes yet) [estimated by Bayesian average]
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Status Docs available [build log]
Last success reported on 2015-07-22 [all 1 reports]

Readme for exceptional-0.3.0.0

[back to package description]

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.