tagged-exception-core: Reflect exceptions using phantom types.

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This library provides interface similar to extensible-exceptions. It introduces Throws monad transformer that uses phantom type to tag code that may raise exception. Intention is to make exceptions explicit and to enforce exception handling.

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Properties

Versions	2.0.0.0, 2.1.0.0, 2.2.0.0, 2.2.0.0
Change log	ChangeLog.md
Dependencies	base (>=4.5 && <5), exceptions (>0.6 && <0.9), ghc-prim, mmorph (>=1.0.0 && <1.1), mtl (>=2.1 && <2.3), transformers (>=0.3 && <0.6) [details]
License	BSD-3-Clause
Copyright	Copyright (c) 2009-2016, Peter Trško
Author	Peter Trško
Maintainer	peter.trsko@gmail.com
Category	Control , Error Handling , Exceptions , Failure , Monad , Monads , Phantom Types
Home page	https://github.com/trskop/tagged-exception-core
Bug tracker	https://github.com/trskop/tagged-exception-core/issues
Source repo	head: git clone git://github.com/trskop/tagged-exception-core.git this: git clone git://github.com/trskop/tagged-exception-core.git(tag 2.2.0.0)
Uploaded	by PeterTrsko at 2016-02-02T20:35:32Z

Modules

[Index]

Control
- Monad
  - Control.Monad.TaggedException

Flags

Manual Flags

Name	Description	Default
pedantic	Pass additional flags to GHC.	Disabled

Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info

Downloads

tagged-exception-core-2.2.0.0.tar.gz [browse] (Cabal source package)
Package description (as included in the package)

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Package maintainers

PeterTrsko

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Readme for tagged-exception-core-2.2.0.0

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Tagged Exception Core

Description

Reflect exceptions using phantom types. This library provides core API and others may build on top of it.

Usage Example

Example of reflecting reised exception in type:

{-# LANGUAGE DeriveDataTypeable #-}

import Control.Exception (Exception)

import Control.Monad.TaggedException (Throws)
import qualified Control.Monad.TaggedException as E (liftT, throw)
import Data.Typeable (Typeable)


data NotReady = NotReady String
    deriving (Show, Typeable)
        -- Both required by Exception class

instance Exception NotReady

myFunction :: Input -> Throws NotReady IO Output
myFunction input = do

    -- ... some stuff ...

    -- isReady :: Input -> IO Bool
    ready <- E.liftT $ isReady input
    unless ready
        . E.throw $ NotReady "Resource of myFunction is not ready."

    -- ... some other stuff ...

License

The BSD 3-Clause License, see LICENSE file for details.

Contributions

Contributions, pull requests and bug reports are welcome! Please don't be afraid to contact author using GitHub or by e-mail.