System.Exit.Lens

These prisms can be used with the combinators in Control.Exception.Lens.

Documentation

class AsExitCode p f t where

Exit codes that a program can return with:

Minimal complete definition

Nothing

Methods

_ExitCode :: Optic' p f t ExitCode

_ExitCode :: Equality' ExitCode      ExitCode
_ExitCode :: Prism'    SomeException ExitCode

Instances

(Choice p, Applicative f) => AsExitCode p f SomeException

AsExitCode p f ExitCode

_ExitFailure :: (AsExitCode p f t, Choice p, Applicative f) => Optic' p f t Int

indicates program failure with an exit code. The exact interpretation of the code is operating-system dependent. In particular, some values may be prohibited (e.g. 0 on a POSIX-compliant system).

_ExitFailure :: Prism' ExitCode      Int
_ExitFailure :: Prism' SomeException Int

_ExitSuccess :: (AsExitCode p f t, Choice p, Applicative f) => Optic' p f t ()

indicates successful termination;

_ExitSuccess :: Prism' ExitCode      ()
_ExitSuccess :: Prism' SomeException ()