[Haskell-cafe] Problem with class Control.Monad.Error noMsg usage
aaronngray.lists at gmail.com
Tue Dec 21 16:28:22 CET 2010
I have been trying to build the Scheme in 24 Hours on WikiBooks :-
But I am getting an error :-
scheme.hs:289:6: `noMsg' is not a (visible) method of class `Error'
`strMsg' is not a (visible) method of class `Error'
with the following :-
instance Error LispError where
noMsg = Default "An error has occurred"
strMsg = Default
if I try importing them :-
import Control.Monad.Error (noMsg, strMsg)
I get the following :-
Module `Control.Monad.Error' does not export `noMsg'
Module `Control.Monad.Error' does not export `strMsg'
Many thanks in advance,
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