[Haskell-beginners] exception, not in IO

[Lyndon Maydwell]

You can turn anything into an IO action with return, or you could catch the
exception at a level where you are performing IO. Would this be what you're
after?


On Sun, Jul 14, 2013 at 7:47 PM, Kees Bleijenberg <
k.bleijenberg at lijbrandt.nl> wrote:

> The app I’am working on, converts a jsonString to another string encoding.
> ****
>
> The function I want to write is  jsonString -> (encoding, errorMsg)  so
> String-> (String, String) ****
>
> For this purpose I have a typeable datastructure Glass. Because it is
> typeable I can do (decodeJSON jsonString) :: Glass****
>
> But sometimes the jsonString is not valid (misformed or wrong fields).
> decodeJSON then throws a exception.  I want to****
>
> catch that exection and transform the result to something like (“” ,
> theErrorMsg). Unfortunately all catch functions want IO parameters. ****
>
> What can I do?****
>
> ** **
>
> Kees****
>
> ** **
>
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