name:
  partial-handler
version: 1.0.0.0
x-revision: 1
synopsis:
  A composable exception handler
description:
  If you have ever had to compose an exception handler for exceptions of multiple types, 
  you know how frustraiting it can get. 
  This library approaches this issue by providing a composable exception handler type,
  which has a Monoid instance.
  .
  Composability means that you can define custom partial handlers and 
  reuse them by composing other handlers from them. 
  .
  Here is an example of a composable partial handler,
  which only defines what to do in case of a ThreadKilled exception
  (the code uses the LambdaCase extension):
  .
  >ignoreThreadKilled :: PartialHandler ()
  >ignoreThreadKilled = 
  >  typed $ \case 
  >    ThreadKilled -> Just $ return ()
  >    _ -> Nothing
  .
  Here's how you can construct a handler of type @SomeException -> IO ()@
  using this library:
  .
  >totalizeRethrowing $
  >  ignoreThreadKilled <>
  >  onAlreadyExists (putStrLn "Already exists")
  .
  and here is how you would do it traditionally (with the MultiWayIf extension):
  .
  >\e -> if 
  >  | Just ThreadKilled <- fromException e -> 
  >      return ()
  >  | Just e' <- fromException e, isAlreadyExistsError e' ->
  >      putStrLn "Already exists"
  >  | otherwise -> 
  >      throwIO e
  .
  Putting all the syntactic trickery to make it shorter aside, 
  this handler is a monolith block of code. 
  Unlike with PartialHandler you can neither decompose it into simpler ones,
  nor compose it with other handlers to form a more complex one.
category:
  Exceptions, Error Handling, Failure
homepage:
  https://github.com/nikita-volkov/partial-handler 
bug-reports:
  https://github.com/nikita-volkov/partial-handler/issues 
author:
  Nikita Volkov <nikita.y.volkov@mail.ru>
maintainer:
  Nikita Volkov <nikita.y.volkov@mail.ru>
copyright:
  (c) 2014, Nikita Volkov
license:
  MIT
license-file:
  LICENSE
build-type:
  Simple
cabal-version:
  >=1.10


source-repository head
  type:
    git
  location:
    git://github.com/nikita-volkov/partial-handler.git


library
  hs-source-dirs:
    library
  other-modules:
  exposed-modules:
    PartialHandler
  build-depends:
    base >= 4.6 && < 4.9
  ghc-options:
    -funbox-strict-fields
  default-extensions:
    LambdaCase
  default-language:
    Haskell2010