On Sun, 2006-09-17 at 18:31 +0200, Cédric Paternotte wrote:
Hi,
I was wondering whether Yhc was able to provide dynamic loading of modules.
Let's say I'd wanted to do something like :
myFiboFunction <- loadModule "myPlugin.hbc" "myFiboFunction" putStrlLn $ myFiboFunction 10
Is it possible to achieve this in the current state of Yhc ? I know there's an API out there to load bytecodes at runtime but I'm not sure it's meant to do that...
Hi Cedric, There is indeed a RuntimeAPI, though it's still in the process of being written so it's a bit low level. At somepoint we'll write a user-friendly library over the top but at present your example would be: import YHC.Runtime.API main = do let typ = undefined :: Int -> Int fibo <- loadFromModule "MyPlugin" "myFiboFunction" typ putStrLn $ show $ fibo 10 loadFromModule :: String -> String -> a -> IO a loadFromModule mod obj typ = do pluginModule <- moduleLoad mod case pluginModule of Nothing -> error $ "couldn't load module '"++mod++"'" Just m -> do fiboNode <- moduleLookupNode m obj case fiboNode of Nothing -> error $ "could not find '"++obj++ "' in module '"++mod++"'" Just n -> do typRep <- getType typ withNode n typRep $ \ fibo -> return fibo Notice that it's necessary to give a dummy parameter of the correct type to keep the type system happy. Also be wary that the system currently doesn't check that the type is correct so doing: ... let typ = undefined :: Float -> Char .. Will compile and even execute, but will prompty crash horribly. In future we'll add type checking so it'll give a sensible runtime error. Hope that helps :-) Tom