I don't know, but:

number
-- definition
= do { num <- natural ; return $ num }
-- desugar
= natural >>= \num -> return $ num
-- apply ($)
= natural >>= \num -> return num
-- eta elimination (f == \x -> f x)
= natural >>= return
-- monad law
= natural

(modulo monomorphism restriction, since number doesn't take any arguments and doesn't have a type signature)

  -- ryan

On Tue, Sep 29, 2009 at 12:54 AM, Anatoly Yakovenko <aeyakovenko@gmail.com> wrote:
number = do { num <- natural
           ; return $ num
           }
main = do
  txt <- hGetContents stdin
  print $ parse number "stdin" txt


why doesn't that work?
_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe