如何将外部导出函数的参数传递给Pipe？

1 回答

• 1

  这是 pipes-concurrency 旨在做的许多事情之一 . 你所做的是 spawn 一个缓冲区，每次调用派生的 tick 函数时，它都会将其参数填充到该缓冲区中 . 然后你可以拥有一个管道流来自该缓冲区的所有内容 .

  import Control.Concurrent.Async
  import Pipes
  import Pipes.Concurrent
  import qualified Pipes.Prelude as P
  
  -- Your FFI tick function, which we will wrap with a derived function
  ffi_tick :: Integer -> Float -> Float -> IO Int
  ffi_tick _ _ _ = return 0
  
  -- A data structure just to simplify the types
  -- In theory I could have just used a tuple
  data Ticker = Ticker
      { _tick  :: Integer -> Float -> Float -> IO Int
      , _input :: Input (Integer, Float, Float)
      }
  
  -- This is in charge of buffer initialization and deriving the new
  -- tick function
  makeTicker :: IO Ticker
  makeTicker = do
      (output, input) <- spawn Unbounded
      let tick x y z = do
              atomically $ send output (x, y, z)
              ffi_tick x y z
      return (Ticker tick input)
  
  -- This is example code showing how you would use it    
  main = do
      Ticker tick input <- makeTicker
      a <- async $ runEffect $ fromInput input >-> P.print
      tick 1 2.0 3.0
      tick 4 5.0 6.0
      tick 7 8.0 9.0
      wait a
  

  回复于 2024-04-30T04:40:43+08:00