[jhc] bracket_ issue and fix

[Korcan Hussein]

Hello, I've been tyring to modify the Haskell SDL bindings from hackage to get it to work on jhc (people should not use Haskell extensions in binding libraries!!!) and I had a problem with a piece of code that was using bracket_ but I did find a solution, the error message was:

[1 of 1] Graphics.UI.SDL.General(.......................................jhc: user error (
What:    failure
Why:     boxyMatch failure: (Jhc.Prim.IO Jhc.Basics.()) (s629 -> Jhc.Prim.IO s630)
Where:   on line 148 in General.hs
in the application
   Control.Exception.bracket_
  (Graphics.UI.SDL.General.init Graphics.UI.SDL.General.20_flags)
  Graphics.UI.SDL.General.quit
  Graphics.UI.SDL.General.21_action
in
   Graphics.UI.SDL.General.withInit        {- on line 148 -}
in the function binding
   Graphics.UI.SDL.General.withInit Graphics.UI.SDL.General.20_flags
  Graphics.UI.SDL.General.21_action
  = Control.Exception.bracket_
      (Graphics.UI.SDL.General.init Graphics.UI.SDL.General.20_flags)
      Graphics.UI.SDL.General.quit
      Graphics.UI.SDL.General.21_action        {- on line 148 -})

My suspicion was that the type signature for bracket_ wasn't exactly the same as defined in Haskell98 so I copied from haddoc docs the defintion and made bracket2_ function:

bracket2_ :: IO a -> IO b -> IO c -> IO c
bracket2_ before after thing = bracket before (const after) (const thing)

Then it all works fine, when I was googling the problem I think someone else had it too so hopefully if another person gets it they can find this :)