mapM_ for bytestring
lemming at henning-thielemann.de
Sun Sep 1 20:55:10 CEST 2013
On Sun, 1 Sep 2013, Artyom Kazak wrote:
> On Sun, 01 Sep 2013 17:16:49 +0400, Henning Thielemann
> <lemming at henning-thielemann.de> wrote:
>>> Yeah, the signatures for mapM_ and mapM would respectively be
>>> mapM_ :: Monad m => (Word8 -> m b) -> ByteString -> m ()
>> This one should not be a big problem, but could be done by calling mapM_
>> on the result of ByteString.unpack.
> As I’ve said, mapM_ through ByteString.unpack is four times slower than
> the hand-written version. I find it unacceptable that a simple counting
> sort *can’t* be written efficiently for ByteString without importing
> Data.ByteString.Unsafe, Foreign.Ptr and friends.
A possible solution might be fusion rules for ByteString.unpack and mapM_.
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