2014-03-03 27 views
3

我一直在使用Haskell插件包将字符串编译为可在运行时在Haskell中使用的函数/值。但是,我遇到了一个问题:当我尝试使用相同的名称加载不同的值时,它只会给出第一个值。Haskell插件在重新编译文件时提供了旧值

这是我的测试文件:

import System.Plugins 
import System.IO.Temp 
import System.Directory 


deleteIfExists :: String -> IO() 
deleteIfExists filePath = do 
    exists <- doesFileExist filePath 
    if exists 
    then 
     (removeFile filePath) 
    else 
     (return()) 

compileInt :: String -> IO Int 
compileInt codeMinusModule = do 

    withTempDirectory "./.tmp" "__compileTemp" $ \path -> do 
    let filePath = (path ++ "/GetInt.hs") 
    let code = "module GetInt where\n" ++ codeMinusModule 

    deleteIfExists filePath 
    writeFile filePath code 

    status <- makeAll filePath [] 
    objectPath <- 
     case status of 
     MakeSuccess _ opath -> return opath 
     MakeFailure elist -> error $ "Couldn't make object:\n" ++ (concat elist) 


    strat <- loadInt objectPath path 

    deleteIfExists path 

    return strat 
    where 
     loadInt objectPath folderPath = do 
     loadStatus <- load objectPath [folderPath] [] "myInt" 
     case loadStatus of 
      LoadFailure msg -> error $ "Failed to compile " ++ (concat msg) 
      LoadSuccess _ strat -> return strat 

而且我ghci中运行:

*Main> compileInt "myInt = 4" 
Loading package array-0.4.0.1 ... linking ... done. 
... 
4 
*Main> compileInt "myInt = 3" 
4 

即使当我给它一个不同的值,它使旧的。我删除了我的临时目录和所有内容。

这是插件包的固有限制,还是我做错了什么?

回答

2

您只需要在第二次加载之前调用unloadAll或类似软件。

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