examples/decode.hs

   1 -- http://www.haskellforall.com/2014/02/pipes-parse-30-lens-based-parsing.html
   2
   3 import Data.ByteString (ByteString)
   4 import Data.Text       (Text)
   5 import Lens.Family.State.Strict (zoom)
   6 import Pipes
   7 import Pipes.Parse
   8 import qualified Pipes.ByteString as ByteString
   9 import qualified Pipes.Text       as Text
  10
  11 -- Retrieve all `Text` chunks up to 10 characters
  12 parser :: Monad m => Parser ByteString m [Text]
  13 parser = zoom (Text.decodeUtf8 . Text.splitAt 10) drawAll
  14
  15 main = do
  16     (textChunks, leftovers) <- runStateT parser ByteString.stdin
  17     print textChunks
  18
  19     -- Now print the remaining `ByteString` chunks
  20     byteChunks <- evalStateT drawAll leftovers
  21     print byteChunks
  22 {-
  23 $ ./decode
  24 Hello, 世界!!!<Enter>
  25 ["Hello, \19990\30028!"]
  26 abcdefg<Enter>
  27 <Ctrl-D>
  28 ["!!\n","abcdefg\n"]
  29
  30 -}