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Today's Topics:
1. Re: Hints on how to remove unsafePerformIO from my
function? (Stephen Tetley)
2. Re: Hints on how to remove unsafePerformIO from my
function? (David McBride)
3. Re: Hints on how to remove unsafePerformIO from my
function? (David McBride)
4. Re: Hints on how to remove unsafePerformIO from my function?
(Brent Yorgey)
----------------------------------------------------------------------
Message: 1
Date: Mon, 19 Jul 2010 15:41:31 +0100
From: Stephen Tetley <[email protected]>
Subject: Re: [Haskell-beginners] Hints on how to remove
unsafePerformIO from my function?
Cc: [email protected]
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=ISO-8859-1
How about unsafeInterleaveIO? - You might have to experiment where to
put it, but you shouldn't need the local unstrict definition.
Because it doesn't violate type safety it is considered less heinous
than unsafePerformIO.
------------------------------
Message: 2
Date: Mon, 19 Jul 2010 11:09:02 -0400
From: David McBride <[email protected]>
Subject: Re: [Haskell-beginners] Hints on how to remove
unsafePerformIO from my function?
To: Stephen Tetley <[email protected]>
Cc: [email protected]
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
I tried this:
fetchUDPSIP :: TChan a -> TChan B.ByteString -> IO ()
fetchUDPSIP commands chan = do
sock <- getUDPSocket 5060
results <- (mapM unsafeInterleaveIO . repeat . getUDP) sock
mapM_ (atomically . writeTChan chan) results
fetchLine = do
results <- (mapM unsafeInterleaveIO . repeat) Prelude.getLine
mapM_ Prelude.putStrLn results
But it seems to have become strict again in that neither version will return
any results until it has gotten everything it can.
Also I'm not sure, but I'm pretty sure any "unsafe" function is still going
to have the original problem where it causes all other threads to stop while
it performs, so I don't think I can use unsafe anything at all and have my
program work properly.
On Mon, Jul 19, 2010 at 10:41 AM, Stephen Tetley
<[email protected]>wrote:
> How about unsafeInterleaveIO? - You might have to experiment where to
> put it, but you shouldn't need the local unstrict definition.
>
> Because it doesn't violate type safety it is considered less heinous
> than unsafePerformIO.
> _______________________________________________
> Beginners mailing list
> [email protected]
> http://www.haskell.org/mailman/listinfo/beginners
>
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Message: 3
Date: Mon, 19 Jul 2010 11:18:28 -0400
From: David McBride <[email protected]>
Subject: Re: [Haskell-beginners] Hints on how to remove
unsafePerformIO from my function?
To: [email protected]
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Okay, I figured this out on my own. This isn't as elegant but it definitely
works:
fetchUDPSIP :: TChan a -> TChan B.ByteString -> IO ()
fetchUDPSIP commands chan = do
sock <- getUDPSocket 5060
loop sock
where
loop sock = do
result <- getUDP sock
(atomically . writeTChan chan) result
loop sock
fetchLine = do
loop
where
loop = do
result <- Prelude.getLine
Prelude.putStrLn result
loop
On Mon, Jul 19, 2010 at 11:09 AM, David McBride <[email protected]>wrote:
> I tried this:
>
> fetchUDPSIP :: TChan a -> TChan B.ByteString -> IO ()
> fetchUDPSIP commands chan = do
> sock <- getUDPSocket 5060
> results <- (mapM unsafeInterleaveIO . repeat . getUDP) sock
>
> mapM_ (atomically . writeTChan chan) results
>
> fetchLine = do
> results <- (mapM unsafeInterleaveIO . repeat) Prelude.getLine
> mapM_ Prelude.putStrLn results
>
> But it seems to have become strict again in that neither version will
> return any results until it has gotten everything it can.
>
> Also I'm not sure, but I'm pretty sure any "unsafe" function is still going
> to have the original problem where it causes all other threads to stop while
> it performs, so I don't think I can use unsafe anything at all and have my
> program work properly.
>
>
> On Mon, Jul 19, 2010 at 10:41 AM, Stephen Tetley <[email protected]
> > wrote:
>
>> How about unsafeInterleaveIO? - You might have to experiment where to
>> put it, but you shouldn't need the local unstrict definition.
>>
>> Because it doesn't violate type safety it is considered less heinous
>> than unsafePerformIO.
>> _______________________________________________
>> Beginners mailing list
>> [email protected]
>> http://www.haskell.org/mailman/listinfo/beginners
>>
>
>
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------------------------------
Message: 4
Date: Mon, 19 Jul 2010 17:20:34 +0100
From: Brent Yorgey <[email protected]>
Subject: Re: [Haskell-beginners] Hints on how to remove
unsafePerformIO from my function?
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
On Mon, Jul 19, 2010 at 11:18:28AM -0400, David McBride wrote:
> Okay, I figured this out on my own. This isn't as elegant but it definitely
> works:
>
By the way, your code can be simplified using forever; these ought to
be equivalent:
> fetchUDPSIP :: TChan a -> TChan B.ByteString -> IO ()
> fetchUDPSIP commands chan = do
> sock <- getUDPSocket 5060
> forever $ do
> result <- getUDP sock
> (atomically . writeTChan chan) result
>
> fetchLine = forever $ do
> result <- Prelude.getLine
> Prelude.putStrLn result
-Brent
------------------------------
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