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copied!<p>The answer to this question has been given to me elsewhere. The GHC API is capable of doing this. Here are two functions, one of which compiles <code>Target.hs</code>, while the other accesses <code>Target.accessMe</code> (and doesn't require the source code of the <code>Target</code> module to be there anymore).</p> <pre><code>import GHC import DynFlags compile :: String -> IO SuccessFlag compile name = defaultRunGhc $ do dynflags <- getSessionDynFlags let dynflags' = dynflags -- You can change various options here. setSessionDynFlags dynflags' -- (name) can be "Target.hs", "Target", etc. target <- guessTarget name Nothing addTarget target load LoadAllTargets -- Runs something like "ghc --make". </code></pre> <p>That's a function that compiles a given module and returns whether compilation succeeded or not. It uses a <code>defaultRunGhc</code> helper function that is defined as:</p> <pre><code>import GHC.Paths (libdir) defaultRunGhc :: Ghc a -> IO a defaultRunGhc = defaultErrorHandler defaultDynFlags . runGhc (Just libdir) </code></pre> <p>And now a function for fetching a value from the compiled module. The module's source code need not be present at this point.</p> <pre><code>import Unsafe.Coerce (unsafeCoerce) fetch :: String -> String -> IO Int -- Assumes we are fetching an Int value. fetch name value = defaultRunGhc $ do -- Again, you can change various options in dynflags here, as above. dynflags <- getSessionDynFlags let m = mkModule (thisPackage dynflags) (mkModuleName name) setContext [] [(m, Nothing)] -- Use setContext [] [m] for GHC<7. fetched <- compileExpr (name ++ "." ++ value) -- Fetching "Target.accessMe". return (unsafeCoerce fetched :: Int) </code></pre> <p>And that's it!</p>

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