Data.OverloadedLabels

This module defines the IsLabel class which is used by the OverloadedLabels language 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.

On GHC >=8.0.1 we just reexport GHC.OverloadedLabels module.

Oveloaded Labels

class IsLabel l a where

Methods

fromLabel :: Proxy# l -> a

Instances

ModifyField l s t a b => IsLabel l (Modifier s t a b)