The control-monad-exception package

[Tags: library, public-domain]

This package provides explicitly typed, checked 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

Versions0.1, 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
Dependenciesbase (>=3.0 && <4), extensible-exceptions (==0.1.*), monads-fd (==0.0.*), transformers (>=0.0.1 && <0.2) or
base (==4.*), monads-fd (==0.0.*), transformers (>=0.0.1 && <0.2)
LicensePublicDomain
AuthorPepe Iborra
Maintainerpepeiborra@gmail.com
Stabilityexperimental
CategoryControl, Monads
Home pagehttp://github.com/pepeiborra/control-monad-exception
UploadedFri Sep 11 21:28:42 UTC 2009 by PepeIborra
Downloads3162 total (155 in last 30 days)
StatusDocs uploaded by user
Build status unknown [no reports yet]

Modules

[Index]

Flags

NameDescriptionDefault
extensibleexceptionsUse extensible-exception packageDisabled

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

Downloads

Maintainers' corner

For package maintainers and hackage trustees