ghc-exceptional

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. 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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