是否可以使用gtk2hs清理一些代码？

Question

我正在使用haskell和gtk2hs启动GUI.我有一个笔记本小部件,我想用"F1,F2 ... F11"键切换页面.

我的工作代码是:

import Control.Monad.Trans (liftIO)
import Graphics.UI.Gtk

main = do
  initGUI

  builder <- builderNew
  builderAddFromFile builder "M62.glade"

  window <- builderGetObject builder castToWindow "window1"
  notebook <- builderGetObject builder castToNotebook "notebook1"

  window `on` keyPressEvent $ tryEvent $ do "F1" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 0
  window `on` keyPressEvent $ tryEvent $ do "F2" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 1
  window `on` keyPressEvent $ tryEvent $ do "F3" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 2
  window `on` keyPressEvent $ tryEvent $ do "F4" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 3
  window `on` keyPressEvent $ tryEvent $ do "F5" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 4
  window `on` keyPressEvent $ tryEvent $ do "F6" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 5
  window `on` keyPressEvent $ tryEvent $ do "F7" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 6
  window `on` keyPressEvent $ tryEvent $ do "F8" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 7
  window `on` keyPressEvent $ tryEvent $ do "F9" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 8
  window `on` keyPressEvent $ tryEvent $ do "F10" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 9
  window `on` keyPressEvent $ tryEvent $ do "F11" <- eventKeyName
                                            liftIO $ notebookSetCurrentPage notebook 10

  onDestroy window mainQuit
  widgetShowAll window
  mainGUI

是否有更好的方法和/或简明的方法来做到这一点？我试图用'main'来处理它,但只有"F1"才有效.我不知道如何管理这个样板.

Answer 1

我对gtk2hs知之甚少,但是使用forM_循环关键索引应该会有很长的路要走.此外,似乎事件是a MonadPlus,因此模式匹配失败可以有利地替换为guard.

forM_ [0..10] $ \i -> do
    let key = "F" ++ show (i + 1)
    window `on` keyPressEvent $ tryEvent $ do
        pressed <- eventKeyName
        guard (pressed == key)
        liftIO $ notebookSetCurrentPage notebook i