base-4.8.0.0: Basic libraries

Copyright(C) 2008-2014 Edward Kmett
LicenseBSD-style (see the file libraries/base/LICENSE)
MaintainerEdward Kmett <ekmett@gmail.com>
Stabilityprovisional
Portabilityportable
Safe HaskellSafe
LanguageHaskell2010

Data.Void

Description

A logically uninhabited data type, used to indicate that a given term should not exist.

Since: 4.8.0.0

Synopsis

Documentation

data Void Source

Uninhabited data type

Since: 4.8.0.0

Instances

Eq Void Source 
Data Void Source 
Ord Void Source 
Read Void Source

Reading a Void value is always a parse error, considering Void as a data type with no constructors.

Show Void Source 
Ix Void Source 
Generic Void Source 
Exception Void Source 
type Rep Void Source 

absurd :: Void -> a Source

Since Void values logically don't exist, this witnesses the logical reasoning tool of "ex falso quodlibet".

Since: 4.8.0.0

vacuous :: Functor f => f Void -> f a Source

If Void is uninhabited then any Functor that holds only values of type Void is holding no values.

Since: 4.8.0.0