[Haskell-cafe] "back doors" into the IO monad

Gwern Branwen gwern0 at gmail.com
Sun Oct 24 10:43:10 EDT 2010


On Sun, Oct 24, 2010 at 10:22 AM, Nicolas Pouillard
<nicolas.pouillard at gmail.com> wrote:
> On Sun, 24 Oct 2010 00:28:37 +0200, Manlio Perillo <manlio_perillo at libero.it> wrote:
>> Hi.
>>
>> What are the available methods to execute IO actions from pure code?
>>
>> I know only unsafePerformIO and foreign import (to call a non pure
>> foreign function).
>
> unsafeCoerce is a back door for almost everything.
>

The mueval tests also include this fun example: 'runST (unsafeIOToST
(readFile "/etc/passwd"))'

-- 
gwern
http://www.gwern.net/


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