Package Info


Essentially the Maybe type with error messages


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.


[] 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.

[] 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.

[] Add 'exceptIO' function to encapsulate IO errors in the 'Exceptional' monad.

[] Fix bug where 'exceptional' won't compile on 'base < 4.8'. Also move the changelog back to the description so it's more visible.

[] Moved change log to a separate file so Hackage displays it correctly.

[] Documentation enhancements/fixes.

[] Added 'fromMaybe' and 'toMaybe' functions, and a link to the bug tracker.

[] Fixed a typo. won't build. Also added definition of 'empty' for 'Alternative'.

[] Added 'fromEither' and 'toEither' functions.

[] Hackage is terrible. Yet another formatting fix.

[] Yet another formatting fix.

[] Formatting fix to the haddock documentation.

[] Add 'runExceptional' function.

[] Minor documentation changes. No changes to the API.

[] Initial version.

License: BSD-2-Clause



Package Version Update ID Released Package Hub Version Platforms Subpackages info GA Release 2018-08-01 15
  • AArch64
  • ghc-exceptional
  • ghc-exceptional-devel info GA Release 2018-07-30 15
  • ppc64le
  • x86-64
  • ghc-exceptional
  • ghc-exceptional-devel