Can you put the whole example into a github repo and then I will look
at what is wrong?
Matt
On Mon, Feb 6, 2023 at 1:34 PM Eternal Recursion via ghc-devs
<ghc-devs@haskell.org> wrote:
>
> Thanks, Andreas!
>
> I will check out the hint package and also play with verbosity and
> workingDirectory.
>
> I considered using the Cabal library to derive the inputs from the project's
> cabal file, but it does help first to know what the needful inputs are, and
> where to stash them in the DynFlags session settings.
>
> It's got to be one of those "One Weird Trick (tm)" gotcha settings that make
> it suddenly work. It seems obvious what some of the settings mean, but I
> suppose with more familiarity will come appreciation of nuances that make the
> apparently obvious meaning seem obviously wrong.
>
> Sincerely,
>
> Bob
>
> Sent with Proton Mail secure email.
>
> ------- Original Message -------
> On Monday, February 6th, 2023 at 7:53 AM, Andreas Klebinger
> <klebinger.andr...@gmx.at> wrote:
>
> I think this is an ok forum for this kind of question. You could also try the
> haskell mailing list but I'm not sure if you will get more
> help tehre.
>
> I recently played around with the ghc api and I found the `hint` package to
> be quite helpful as an example on how to do various
> things when using the ghc api to implement your own interpreter.
>
> Have you tried setting verbose? Perhaps the include dir is relative to the
> working directory. In that case setting:
>
> , workingDirectory = Just targetDir
> , importPaths = [targetDir] ++ importPaths dynflags
>
> would mean ghc will search in targetDir/targetDir for Lib/Lib2. Should be
> easy to say for sure by enabling verbosity and looking at the output.
>
> Am 06/02/2023 um 13:42 schrieb Eternal Recursion via ghc-devs:
>
> 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
>
> Sent with Proton Mail secure email.
>
> ------- Original Message -------
> On Saturday, February 4th, 2023 at 4:04 PM, Eternal Recursion via ghc-devs
> <ghc-devs@haskell.org> wrote:
>
> 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
>
> Sent with Proton Mail secure email.
>
>
>
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