The control-monad-exception package

[ Tags: control, failure, library, mit, monads ] [ Propose Tags ]

This package provides explicitly typed exceptions as a library.

Example

data Expr = Add Expr Expr | Div Expr Expr | Val Double
eval (Val x)     = return x
eval (Add a1 a2) = do
   v1 <- eval a1
   v2 <- eval a2
   let sum = v1 + v2
   if sum < v1 || sum < v2 then throw SumOverflow else return sum
eval (Div a1 a2) = do
   v1 <- eval a1
   v2 <- eval a2
   if v2 == 0 then throw DivideByZero else return (v1 / v2)
data DivideByZero = DivideByZero deriving (Show, Typeable)
data SumOverflow  = SumOverflow  deriving (Show, Typeable)
instance Exception DivideByZero
instance Exception SumOverflow

GHCi infers the following types

eval :: (Throws DivideByZero l, Throws SumOverflow l) => Expr -> EM l Double
eval `catch` \ (e::DivideByZero) -> return (-1)  :: Throws SumOverflow l => Expr -> EM l Double
runEM(eval `catch` \ (e::SomeException) -> return (-1))  :: Expr -> Double

Properties

Versions 0.1, 0.1.1, 0.1.2, 0.2, 0.3, 0.3.1, 0.3.2, 0.4, 0.4.1, 0.4.2, 0.4.3, 0.4.4, 0.4.5, 0.4.6, 0.4.7, 0.4.8, 0.5, 0.6, 0.8.0, 0.8.0.1, 0.8.0.2, 0.8.0.3, 0.8.0.4, 0.9.0, 0.9.1, 0.10.0, 0.10.1, 0.10.2, 0.10.3, 0.10.3.1, 0.11.1, 0.11.2
Dependencies base (>=3.0 && <4 || >=4.0), extensible-exceptions (==0.1.*), monads-fd (==0.0.*), transformers (>=0.0.1 && <0.2) [details]
License PublicDomain
Author Pepe Iborra
Maintainer pepeiborra@gmail.com
Category Control, Monads
Home page http://github.com/pepeiborra/control-monad-exception
Uploaded Wed May 27 14:21:08 UTC 2009 by PepeIborra
Distributions NixOS:0.11.2
Downloads 7814 total (44 in the last 30 days)
Rating 0.0 (0 ratings) [clear rating]
  • λ
  • λ
  • λ
Status Docs uploaded by user
Build status unknown [no reports yet]
Hackage Matrix CI

Modules

[Index]

Flags

NameDescriptionDefaultType
extensibleexceptions

Use extensible-exception package

DisabledAutomatic

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

Downloads

Maintainer's Corner

For package maintainers and hackage trustees