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

John Meacham john at
Thu Feb 14 15:21:12 EST 2008

On Fri, Feb 08, 2008 at 09:35:34PM +0100, Twan van Laarhoven wrote:
> David Menendez wrote:
>>> Isn't the MonadPlus approach also by-default-safe?
>> Safe, yes, but is it more useful?
> Yes. In this case, take a parsing monad for example. You could write:
>   parseInt :: CharParser () Int
>   parseInt = do ds <- many digit
>                 readM ds
> And it would work automatically. A reading error would be propagated to the 
> parser monad, and it would backtrack/report the error/whatever.

Yes. this is exactly the sort of thing I use this for. (I have had readM
in my standard toolkit for a while).


John Meacham - ⑆⑆john⑈

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