[Haskell-cafe] Converting IO [XmlTree] to [XmlTree]
Manlio Perillo
manlio_perillo at libero.it
Tue Apr 21 09:56:30 EDT 2009
Luke Palmer ha scritto:
> [...]
> Note that it is not always possible to separate IO from pure code.
> As an example, consider an HTTP 1.1 server that read a request body
> containing a number for each line, and return a response body containing
> the sum of the numbers.
>
>
> What?
>
> sumRequest :: String -> String
> -- strips header, sums numbers, returns response
>
> sumServer :: IO ()
> -- reads from socket, writes sumRequest to socket
>
> And many other permutations, with differing degrees of laziness and
> parametericity.
>
As long as you stricly read a string from the socket, this is ok.
But you can not read a string lazily.
Regards Manlio
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