[haskell-pipes] Re: Efficient way to take n bytes from lazy bytestring

[Michael Thompson]

You can if you like apply aeson/attoparsec parsers directly to a 'streaming 
bytestring'. 

      import Streaming
      import qualified Data.ByteString.Streaming.Char8 as Q
      import qualified Data.ByteString.Streaming.Aeson as Aeson
      import Data.Aeson 
      import qualified Data.Attoparsec.ByteString.Streaming as A


I can write things like this (note there is the obvious IsString instance 
for `ByteString m r`):

    >>> (a,b) <- A.parse json' $ void $ Q.splitAt 27 
 "{\"a\":[1,2],\"b\":[3,4] }      xxxxxxxxxxxxxxxxx"    

    >>> a
    Left (Object (fromList [("a",Array [Number 1.0,Number 2.0]),("b",Array 
[Number 3.0,Number 4.0])]))

    >>> Q.length b
    5 :> ()

Obviously one should take account of where in general the bytes one is not 
reading were supposed to be coming from and similar questions.

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