At a guess, because the ghc package defaults to being hidden (it's creating a new ghc instance at runtime, so the visibility of the ghc package when compiling your code is not relevant) you need to do the ghc-api equivalent of "-package ghc". Or for testing just "ghc-pkg expose ghc". On Fri, Aug 2, 2019 at 3:47 PM Sam Halliday wrote:

To answer my own question with a solution and another question:

Sam Halliday writes:

...

I'm mostly interested in gathering information about symbols and their type signatures. As a first exercise: given a module+import section for a haskell source file, I want to find out which symbols (and their types) are available. Like :browse in ghci, but programmatically.

This is answered by Stephen Diehl's blog post on the ghc api! How lucky I am: http://www.stephendiehl.com/posts/ghc_01.html

He points to getNamesInScope

Unfortunately I'm getting zero Names back when loading a file that imports several modules from ghc. Is there something I'm missing in the following?

module Main where

import Control.Monad import Control.Monad.IO.Class import GHC import GHC.Paths (libdir)

main = runGhc (Just libdir) $ do dflags <- getSessionDynFlags void $ setSessionDynFlags $ dflags { hscTarget = HscInterpreted , ghcLink = LinkInMemory } addTarget $ Target (TargetFile "exe/Main.hs" Nothing) False Nothing res <- load LoadAllTargets liftIO $ putStrLn $ showPpr dflags res names <- getNamesInScope liftIO $ putStrLn $ "seen " <> (show $ length names) <> " Names"

-- Best regards, Sam _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

-- brandon s allbery kf8nh allbery.b@gmail.com

No, those are in base. But I don't think you would be seeing imported names as such there, come to think of it, only names declared locally. On Fri, Aug 2, 2019 at 4:06 PM Sam Halliday wrote:

Brandon Allbery writes:

...

At a guess, because the ghc package defaults to being hidden (it's creating a new ghc instance at runtime, so the visibility of the ghc package when compiling your code is not relevant) you need to do the ghc-api equivalent of "-package ghc". Or for testing just "ghc-pkg expose ghc".

Hmm, would that also explain why the Prelude and Control.Monad modules are not shown either?

Is there a way to expose all modules programmatically?

...

On Fri, Aug 2, 2019 at 3:47 PM Sam Halliday

wrote:

...

...

To answer my own question with a solution and another question:

Sam Halliday writes:

...

I'm mostly interested in gathering information about symbols and their type signatures. As a first exercise: given a module+import section for a haskell source file, I want to find out which symbols (and their types) are available. Like :browse in ghci, but programmatically.

This is answered by Stephen Diehl's blog post on the ghc api! How lucky I am: http://www.stephendiehl.com/posts/ghc_01.html

He points to getNamesInScope

Unfortunately I'm getting zero Names back when loading a file that imports several modules from ghc. Is there something I'm missing in the following?

module Main where

import Control.Monad import Control.Monad.IO.Class import GHC import GHC.Paths (libdir)

main = runGhc (Just libdir) $ do dflags <- getSessionDynFlags void $ setSessionDynFlags $ dflags { hscTarget = HscInterpreted , ghcLink = LinkInMemory } addTarget $ Target (TargetFile "exe/Main.hs" Nothing) False Nothing res <- load LoadAllTargets liftIO $ putStrLn $ showPpr dflags res names <- getNamesInScope liftIO $ putStrLn $ "seen " <> (show $ length names) <> " Names"

-- Best regards, Sam _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

-- brandon s allbery kf8nh allbery.b@gmail.com

-- Best regards, Sam

-- brandon s allbery kf8nh allbery.b@gmail.com

Hey Sam, Starting from the implementation of :browse and going through the call graph in: https://gitlab.haskell.org/ghc/ghc/blob/master/ghc/GHCi/UI.hs gave the following, which works for me: module Main where import Control.Monad import Control.Monad.IO.Class import BasicTypes import DynFlags import GHC import GHC.Paths (libdir) import Maybes import Panic main = runGhc (Just libdir) $ do dflags <- getSessionDynFlags void $ setSessionDynFlags $ dflags { hscTarget = HscInterpreted , ghcLink = LinkInMemory } t <- guessTarget "Main.hs" Nothing setTargets [t] _ <- load LoadAllTargets graph <- getModuleGraph mss <- filterM (isLoaded . ms_mod_name) (mgModSummaries graph) let m = ms_mod ms ms = head mss liftIO . putStrLn $ (show . length $ mss) ++ " modules loaded" mi <- getModuleInfo m let mod_info = fromJust mi dflags <- getDynFlags let names = GHC.modInfoTopLevelScope mod_info `orElse` [] liftIO $ putStrLn $ "seen " <> (show $ length names) <> " Names" -- Best, Artem On Fri, 2 Aug 2019 at 15:47, Sam Halliday wrote:

To answer my own question with a solution and another question:

Sam Halliday writes:

...

I'm mostly interested in gathering information about symbols and their type signatures. As a first exercise: given a module+import section for a haskell source file, I want to find out which symbols (and their types) are available. Like :browse in ghci, but programmatically.

This is answered by Stephen Diehl's blog post on the ghc api! How lucky I am: http://www.stephendiehl.com/posts/ghc_01.html

He points to getNamesInScope

Unfortunately I'm getting zero Names back when loading a file that imports several modules from ghc. Is there something I'm missing in the following?

module Main where

import Control.Monad import Control.Monad.IO.Class import GHC import GHC.Paths (libdir)

main = runGhc (Just libdir) $ do dflags <- getSessionDynFlags void $ setSessionDynFlags $ dflags { hscTarget = HscInterpreted , ghcLink = LinkInMemory } addTarget $ Target (TargetFile "exe/Main.hs" Nothing) False Nothing res <- load LoadAllTargets liftIO $ putStrLn $ showPpr dflags res names <- getNamesInScope liftIO $ putStrLn $ "seen " <> (show $ length names) <> " Names"

-- Best regards, Sam _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs