找不到模块“是" [英] Could not find module `Yesod'

问题描述

我有以下代码:

{-# LANGUAGE TypeFamilies, QuasiQuotes, MultiParamTypeClasses,
             TemplateHaskell, OverloadedStrings #-}

module Simple where
import Yesod
data HelloWorld = HelloWorld

mkYesod "HelloWorld" [parseRoutes|
/ HomeR GET
|]

instance Yesod HelloWorld

getHomeR = defaultLayout [whamlet|Hello World!|]

withHelloWorld  f = toWaiApp HelloWorld >>= f

main = warpDebug 3000 HelloWorld

如果在GHCI中运行，它将正常运行:

If run it in GHCI, it runs normally:

Ok, modules loaded: Simple.
*Simple> main
Application launched, listening on port 3000

但是如果以以下方式运行它:

But if run it as:

wai-handler-devel 3000 Simple withHelloWorld

控制台报告错误:

pshuvaev@pshuvaev-K73SV:~/works/haskell/yesod/SimpleSite$ wai-handler-devel 3000 Simple.hs withHelloWorld
Attempting to interpret your app...
Compile failed: 

Could not find module `Yesod'
Use -v to see a list of the files searched for.

可能是什么问题?Yesod已设置，并显示在 ghc-pkg列表的输出中.

What could be the problem? Yesod is set and it displays in the output of ghc-pkg list.

推荐答案

在Unix系统上，删除〜/.ghc 目录并运行:

On Unix systems remove ~/.ghc directory and run:

ghc-pkg --global recache

在Windows系统上(只是建议)，删除 C:\ Users \ USERNAME \ AppData \ Roaming \ ghc ，然后从命令行(以Admin)重新缓存:

On Windows systems (just suggestion) remove C:\Users\USERNAME\AppData\Roaming\ghc and also recache from the command line (as Admin):

ghc-pkg --global recache

不确定Windows！请检查！

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