Yet another pipes text example

package.cabal

name:                pipetastic
version:             0.1.0.0
build-type:          Simple
cabal-version:       >= 2

executable pipetastic
  main-is:             Main.hs
  build-depends:       base >= 4.10 && < 4.11   ,
                       microlens >= 0.4.8.0     ,
                       text                     ,
                       foldl >= 1.3.0           ,
                       pipes >= 4.3.4           ,
                       pipes-group >= 1.0.7     ,
                       pipes-bytestring >= 2.1.6,
                       pipes-text >= 0.0.2.5
  default-language:    Haskell2010

YetAnotherPipesTextExample.hs

module Main where

import Pipes
import qualified Pipes.Prelude as P
import qualified Pipes.Group as PG
import qualified Pipes.ByteString as PB
import qualified Pipes.Text as PT
import Pipes.Text.Encoding (utf8)
import qualified Control.Foldl as L
import qualified Control.Foldl.Text as LT

import Control.Monad (unless)
import Data.Text.Lazy (Text)
import Lens.Micro.Extras (view)

test :: [Text] -> Bool
test _ = True

main :: IO ()
main = do
    result <- next -- peek one value
            . (\producer -> producer >-> P.dropWhile (not . test))
            . L.purely PG.folds L.list -- collect streamed groups of lines
            . view (PG.chunksOf 3)
            . L.purely PG.folds LT.lazy -- convert streamed text lines to lazy text
            . view (utf8 . PT.lines)
            $ PB.stdin
    case result of
        Left leftovers -> -- no failures, potentially a stream of leftovers
            do isNull <- P.null leftovers
               unless isNull $ print "Decoding error."
        Right (e,_) -> -- some group failed
            do print "Test failed for group:"
               print e