平安!我使用 Yesod 编写了以下程序:

main = warp 2060 $ 
  onStatic "home" (dispatchTo $ return $ h1 $ toHtml "Sheepfold") 

但是当我运行它时，出现以下错误:

No instance for (YesodDispatch 
                   (Control.Monad.Trans.Writer.Lazy.Writer LiteApp ())) 
  arising from a use of `warp' 
Possible fix: 
  add an instance declaration for 
  (YesodDispatch (Control.Monad.Trans.Writer.Lazy.Writer LiteApp ())) 
In the expression: warp 2060 
In the expression: 
  warp 2060 
  $ onStatic "home" (dispatchTo $ return $ h1 $ toHtml "Sheepfold") 
In an equation for `main': 
    main 
      = warp 2060 
        $ onStatic "home" (dispatchTo $ return $ h1 $ toHtml "Sheepfold") 

有人能帮忙吗？

请您参考如下方法:

您需要调用 liteApp。参见 this example for a demonstration .