Re: Old bug hanging around?
[email protected] Wed, 7 Mar 2007 23:45:17 +0000 (GMT)
| Newsgroups | gmane.comp.lang.haskell.hugs.user |
|---|---|
| Message-ID | <[email protected]> |
> On Wed, Mar 07, 2007 at 10:54:55PM +0000, [email protected] wrote: > > io f = interact (unlines . f . lines) > > showln = (++ "\n") . show > > > > -- Compute a simple cksum of a file > > > > main = interact $ showln . foldl' k 5381 > > where k h c = h * 33 + ord c > > > > ======== > > > > Hugs> :load chksum.hs > > ERROR "chksum.hs":15 - Unresolved top-level overloading > > *** Binding : showln > > *** Outstanding context : Show b > > > > Text.Printf> > > > > This error has been around for a while. > > Yes, it's a documented divergence from Haskell 98 in the handling of > the Monomorphism Restriction. > > Workarounds are to give an explicit signature for showln, or to tweak > the definition so it's a function: > > showln x = show x ++ "\n" > > (or, better) > > showln x = shows x "\n" That Works. Thanks, Dave