
29 Sep
2009
29 Sep
'09
8:29 a.m.
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
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