Proposal: Add Text.Read.maybeRead :: Read a => String -> Maybe a

[Jeff Polakow]

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 at haskell.org wrote on 02/07/2008 01:46:48 PM:

> 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.
> 
> [attachment "maybeRead.patch" deleted by Jeff Polakow/db/dbcom] 
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