On Wed, Aug 22, 2007 at 12:09:21PM -0400, Gwern Branwen wrote:
, ((modMask .|. shiftMask, xK_g ), spawn $ "google" ++ unsafePerformIO(getSelection))
But notice I used unsafePerformIO. The reason is that if you try to simply concatenate "google" and getSelection, there's a type mismatch. You can then try using liftM to do it, like ("google"++) `liftM` getSelection, and that will work well. Unfortunately, spawn :: String -> X (), so spawn needs to be lifted. (The internal /bin/sh stuff apparently requires a String too, so it's not spawn's fault.) But if you go 'spawn (("google"++) `liftM` getSelection' - which on its own would work - the resulting type is something like IO ( X ()). And that just can't be allowed inside 'keys'. At least, the only solution I could find was to just slice the Gordian knot and avoid introducing the IO signature in the first place. Monads may be the greatest thing since sliced bread, but most of the time they're just a pain :(
It's a lot easier if you use the 'io' function, type forall a. IO a -> X a : spawn . ("google " ++) =<< io getSelection Stefan