[Haskell-cafe] Conditional IO ?

[Arlen Cuss]

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On 20/06/11 18:00, Dmitri O.Kondratiev wrote:
> Hi,
> What is right way to do conditional IO?
> For example, I need to write to file errors only in case they exist,
> otherwise my function should do nothing:
> 
> handleParseErrors errors
>   | (not . null) errors =  writeFile "parse-errors.txt" (show errors)
>   | otherwise = ?
> 
> What should be an 'otherwise' case ?

How about `return ()'?
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