ImportHidden.hs

module ImportHidden where

import DynFlags
import FastString
import Language.Haskell.TH.Syntax
import Module
import Packages
import TcRnMonad (TcM)
import TcSplice ()
import Unsafe.Coerce

unsafeRunTcM :: TcM a -> Q a
unsafeRunTcM m = unsafeCoerce (\_ -> m)

qGetDynFlags :: Q DynFlags
qGetDynFlags = unsafeRunTcM getDynFlags

qFindUnitId :: String -> Q UnitId
qFindUnitId pkg_name = do
  dflags <- qGetDynFlags
  comp_id <- case lookupPackageName dflags $ PackageName $ fsLit pkg_name of
    Just comp_id -> pure comp_id
    _ -> fail $ "Package not found: " ++ pkg_name
  pure $ DefiniteUnitId $ DefUnitId $ componentIdToInstalledUnitId comp_id

importHidden :: String -> String -> String -> Q Exp
importHidden pkg_name mod_name val_name = do
  unit_id <- qFindUnitId pkg_name
  pure $
    VarE $
      Name
        (OccName val_name)
        (NameG VarName (PkgName (unitIdString unit_id)) (ModName mod_name))