base-4.9.0.0: Basic libraries

Copyright(c) Adam Gundry 2015
Licensesee libraries/base/LICENSE
Maintainercvs-ghc@haskell.org
Stabilityinternal
Portabilitynon-portable (GHC extensions)
Safe HaskellNone
LanguageHaskell2010

GHC.OverloadedLabels

Description

This module defines the IsLabel class is used by the OverloadedLabels extension. See the wiki page for more details.

The key idea is that when GHC sees an occurrence of the new overloaded label syntax #foo, it is replaced with

fromLabel (proxy# :: Proxy# "foo") :: alpha

plus a wanted constraint IsLabel "foo" alpha.

Documentation

class IsLabel x a where Source #

Minimal complete definition

fromLabel

Methods

fromLabel :: Proxy# x -> a Source #