If this is the wrong forum for this question (which as I think about it, I suppose it is) then redirection to a more appropriate mailing list or forum (or any advice, really) would be appreciated. I just figured this would be the forum with the best understanding of how the GHC API works (and has changed over time), and my longer term goal is indeed to contribute to it after I get past my learning curve.
Sincerely,
Bob
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------- Original Message -------
On Saturday, February 4th, 2023 at 4:04 PM, Eternal Recursion via ghc-devs
Hi Everyone!
I'm new here, trying to learn the GHC API. using 944 with cabal 3.8.1.0.
How do I correctly set a GHC Session's DynFlags (and/or other properties) to ensure local libraries imported by the main target are resolved properly at compile time?
What flags need to be set so that GHC is able to load/analyze/compile all relevant Libraries in a package?
This is my current code:
withPath :: FilePath -> IO () withPath target = do let targetDir = takeDirectory target let targetFile = takeFileName target listing <- listDirectory targetDir let imports = filter (\f -> takeExtension f == ".hs") listing print imports let moduleName = mkModuleName targetFile g <- defaultErrorHandler defaultFatalMessager defaultFlushOut $ runGhc (Just libdir) $ do initGhcMonad (Just libdir) dynflags <- getSessionDynFlags setSessionDynFlags $ dynflags { ghcLink = LinkInMemory , ghcMode = CompManager , backend = Interpreter , mainModuleNameIs = moduleName , workingDirectory = Just targetDir , importPaths = [targetDir] ++ importPaths dynflags }
targets <- mapM (\t -> guessTarget t Nothing Nothing) imports setTargets targets setContext [ IIDecl $ simpleImportDecl (mkModuleName "Prelude") ] load LoadAllTargets liftIO . print . ppr =<< getTargets getModuleGraph putStrLn "Here we go!" print $ ppr $ mgModSummaries g putStrLn "☝️ "
However, when I run it (passing to example/app/Main.hs, in which directory are Lib.hs and Lib2.hs, the latter being imported into Main), I get:
$ cabal run cli -- example/app/Main.hs Up to date ["Main.hs","Lib.hs","Lib2.hs"] [main:Main.hs, main:Lib.hs, main:Lib2.hs] Here we go! [ModSummary { ms_hs_hash = 23f9c4415bad851a1e36db9d813f34be ms_mod = Lib, unit = main ms_textual_imps = [(, Prelude)] ms_srcimps = [] }, ModSummary { ms_hs_hash = e1eccc23af49f3498a5a9566e63abefd ms_mod = Lib2, unit = main ms_textual_imps = [(, Prelude)] ms_srcimps = [] }, ModSummary { ms_hs_hash = 5f6751d7f0d5547a1bdf39af84f8c07f ms_mod = Main, unit = main ms_textual_imps = [(, Prelude), (, Lib2)] ms_srcimps = [] }] ☝
example/app/Main.hs:4:1: error: Could not find module ‘Lib2’ Use -v (or `:set -v` in ghci) to see a list of the files searched for. | 4 |import qualified Lib2 as L2 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ cli: example/app/Main.hs:4:1: error: Could not find module `Lib2' Use -v (or `:set -v` in ghci) to see a list of the files searched for.
What do I need to do differently to make this work?
I have a local Cabal file I could use, but to know what I need out of it, I need to understand the minimum required info to get this to work. TIA!
Sincerely,
Bob
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