[Haskell-cafe] Problem with class Control.Monad.Error noMsg usage

Ross Paterson ross at soi.city.ac.uk
Tue Dec 21 23:03:27 CET 2010

On Tue, Dec 21, 2010 at 03:28:22PM +0000, Aaron Gray wrote:
> I have been trying to build the Scheme in 24 Hours on WikiBooks :-
>     http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours
>     http://jonathan.tang.name/files/scheme_in_48/code/listing10.hs
> But I am getting an error :- 
>     scheme.hs:289:6: `noMsg' is not a (visible) method of class `Error'
>     scheme.hs:290:6:
>          `strMsg' is not a (visible) method of class `Error'

I don't get that here.  Perhaps you're using an old version of monads-fd
(  I'd recommend installing mtl- instead.

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