Reputation: 8433
I've been using the Haskell plugins package to compile strings into functions/values which can be used in Haskell at runtime. However, I've got a problem: when I try to load different values with the same name, it only gives the first value.
Here's my test file:
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
And my ghci run:
*Main> compileInt "myInt = 4"
Loading package array-0.4.0.1 ... linking ... done.
...
4
*Main> compileInt "myInt = 3"
4
Even when I give it a different value, it keeps the old one. I delete my temp directories and everything.
Is this an inherent limitation of the plugins package, or am I doing something wrong?
Upvotes: 3
Views: 99
Reputation: 1502
You just need to call unloadAll
or similar before loading a second time.
Upvotes: 2