Merge remote-tracking branch 'kazu/master'

Language/Haskell/GhcMod/Find.hs

@@ -34,7 +34,7 @@ import Name (getOccString)
 import System.Directory (doesDirectoryExist, getAppUserDataDirectory, doesFileExist, getModificationTime)
 import System.FilePath ((</>), takeDirectory)
 import System.IO
-import System.Environment (getExecutablePath)
+import System.Environment
 
 #ifndef MIN_VERSION_containers
 #define MIN_VERSION_containers(x,y,z) 1
@@ -90,11 +90,18 @@ loadSymbolDb = SymbolDb <$> readSymbolDb
 ghcModExecutable :: IO FilePath
 #ifndef SPEC
 ghcModExecutable = do
-    dir <- takeDirectory <$> getExecutablePath
+    dir <- getExecutablePath'
     return $ dir </> "ghc-mod"
 #else
 ghcModExecutable = return "dist/build/ghc-mod/ghc-mod"
 #endif
+ where
+    getExecutablePath' :: IO FilePath
+# if __GLASGOW_HASKELL__ >= 706
+    getExecutablePath' = takeDirectory <$> getExecutablePath
+# else
+    getExecutablePath' = return ""
+# endif
 
 readSymbolDb :: IO (Map Symbol [ModuleString])
 readSymbolDb = handle (\(SomeException _) -> return M.empty) $ do

Language/Haskell/GhcMod/Monad.hs

@@ -127,10 +127,22 @@ instance Error GhcModError where
 
 ----------------------------------------------------------------
 
+-- | A constraint alias (-XConstraintKinds) to make functions dealing with
+-- 'GhcModT' somewhat cleaner.
+--
+-- Basicially an @IOish m => m@ is a 'Monad' supporting arbitrary 'IO' and
+-- exception handling. Usually this will simply be 'IO' but we parametrise it in
+-- the exported API so users have the option to use a custom underlying monad.
 type IOish m = (Functor m, MonadIO m, MonadBaseControl IO m)
 
 type GhcMod a = GhcModT (ErrorT GhcModError IO) a
 
+-- | The GhcMod monad transformer data type. This is basically a wrapper around
+-- RWST with custom instances for 'GhcMonad' and it's constraints.
+--
+-- The inner monad should have instances for 'MonadIO' and 'MonadBaseControl'
+-- 'IO'. Most @mtl@ monads already have 'MonadBaseControl' 'IO' instances, see
+-- the @monad-control@ package.
 newtype GhcModT m a = GhcModT {
       unGhcModT :: RWST GhcModEnv GhcModWriter GhcModState m a
     } deriving (Functor