| I would think the easiest way to go about this would be to extend the | rules pragma. | | {-# RULES "shift/const-inline" forall x y# . shift x y# = ... #-} | | where variables ending in # will only match constants known at compile time Interesting idea. GHC can do that *internally* using a "BuiltinRule", and it's internal precisely because there's no obvious way to say "match only a literal". I suppose that you might also want to say "match only a constructor"? To have a rule for 'f' that would fire only when you saw f (Just x) or f Nothing but not f (g y) For that, a # would not really be appropriate. Would this be valuable? If so, think of a nice syntax. It's not trivial to implement, but not hard either. Simon | -----Original Message----- | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-users-bounces@haskell.org] | On Behalf Of John Meacham | Sent: 18 October 2006 06:37 | To: glasgow-haskell-users@haskell.org | Subject: Re: [Haskell] Expecting more inlining for bit shifting | | On Mon, Oct 09, 2006 at 03:54:41PM +0100, Ian Lynagh wrote: | > It might be possible, but it sounds tricky. I guess it would have to go | > something like "try inlining this, run the simplifier, see if it got | > small enough, if not back out", which could waste a lot of work if it | > fails in lots of cases. | | I would think the easiest way to go about this would be to extend the | rules pragma. | | {-# RULES "shift/const-inline" forall x y# . shift x y# = ... #-} | | where variables ending in # will only match constants known at compile | time. or perhaps.. | | {-# RULES "shift/const-inline" forall x (y::const Int) . shift x y# = ... #-} | | or something like that. | | I imagine such a thing would have other uses as well... | | John | | -- | John Meacham - ⑆repetae.net⑆john⑈ | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users