simple rewrite rule example

22 Jun 2010

      Hi,

I'd like to learn how to use ghc rewrite rules. I simply want to  
replace a function called f by a function called g. I do not  
unterstand why the rule f->g does not fire.

Cheers, Jan

module Main where

{-# RULES
   "f->g"    forall x. f x = g x
   #-}

main :: IO ()
main = print (f 1)

{-# NOINLINE f #-}
f :: a -> Bool
f _ = False

g :: a -> Bool
g _ = True

simple rewrite rule example

Jan Christiansen