converting GhcMonad to IOish.

Language/Haskell/GhcMod/Target.hs

@@ -0,0 +1,39 @@
+module Language.Haskell.GhcMod.Target (
+    setTargetFiles
+  ) where
+
+import Control.Applicative ((<$>))
+import Control.Monad (forM, void, (>=>))
+import DynFlags (ExtensionFlag(..), xopt)
+import GHC (DynFlags(..), LoadHowMuch(..))
+import qualified GHC as G
+import Language.Haskell.GhcMod.DynFlags
+import Language.Haskell.GhcMod.Monad (IOish, GhcModT)
+
+-- | Set the files as targets and load them.
+setTargetFiles :: IOish m => [FilePath] -> GhcModT m ()
+setTargetFiles files = do
+    targets <- forM files $ \file -> G.guessTarget file Nothing
+    G.setTargets targets
+    xs <- G.depanal [] False
+    -- FIXME, checking state
+    loadTargets $ needsFallback xs
+  where
+    loadTargets False = do
+        -- Reporting error A and error B
+        void $ G.load LoadAllTargets
+        mss <- filter (\x -> G.ms_hspp_file x `elem` files) <$> G.getModuleGraph
+        -- Reporting error B and error C
+        mapM_ (G.parseModule >=> G.typecheckModule >=> G.desugarModule) mss
+        -- Error B duplicates. But we cannot ignore both error reportings,
+        -- sigh. So, the logger makes log messages unique by itself.
+    loadTargets True = do
+        df <- G.getSessionDynFlags
+        void $ G.setSessionDynFlags (setModeIntelligent df)
+        void $ G.load LoadAllTargets
+
+needsFallback :: G.ModuleGraph -> Bool
+needsFallback = any (hasTHorQQ . G.ms_hspp_opts)
+  where
+    hasTHorQQ :: DynFlags -> Bool
+    hasTHorQQ dflags = any (`xopt` dflags) [Opt_TemplateHaskell, Opt_QuasiQuotes]