pipeline _ (BangPipeline (s:ss)) = do s' <- runStatement IgnoreE s
                                      ss' <- pipeline IgnoreE $ BangPipeline ss
                                      return $ pipeShells s' ss'
pipeline _ (BangPipeline (s:ss)) = do s' <- runStatement IgnoreE s
                                      ss' <- pipeline IgnoreE $ BangPipeline ss
                                      return $ pipeShells s' ss'
pipeline _ (BangPipeline (s:ss)) = do s' <- runStatement IgnoreE s
                                      ss' <- pipeline IgnoreE $ BangPipeline ss
                                      return $ pipeShells s' ss'