Hello,
Why not allow an arbitrary monad?
readM :: (Monad m, Read a) => String -> String -> m a
readM errMsg s = case reads s of
[(x, "")] -> return x
_ -> fail errMsg
-Jeff
libraries-bounces@haskell.org wrote on 02/07/2008 01:46:48 PM:> [attachment "maybeRead.patch" deleted by Jeff Polakow/db/dbcom]
> This function is typically defined once per project. So its
> about time this safe variant of 'read' made it into the base.
>
> maybeRead :: Read a => String -> Maybe a
> maybeRead s = case reads s of
> [(x, "")] -> Just x
> _ -> Nothing
>
> Consideration period: 1 week.
>
> Patch to Text.Read attached.
>
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