patch applied (packages/base): Control.Monad: +void :: f a -> f ()

[Malcolm Wallace]

Fri Jan  8 13:44:55 PST 2010  gwern0 at gmail.com
  * Control.Monad: +void :: f a -> f ()
  Ignore-this: 4dc07452315f2d1b4941903ff42fc45f
  See http://hackage.haskell.org/trac/ghc/ticket/3292
  Turns m a -> m (). Lets one call functions for their side-effects without
  having to get rid of their return values with '>> return ()'. Very useful
  in many contexts (parsing, IO etc.); particularly good for 'forkIO' and 'forM_',
  as they demand return types of 'IO ()' though most interesting IO functions
  return non-().

    M ./Control/Monad.hs +4

View patch online:
http://darcs.haskell.org/packages/base/_darcs/patches/20100108214455-f7719-4e6f6d291bc2f5e236db07e51c65351cb0195a5c.gz