Reorganize module namespace

- Remove Language.Haskell prefix from all modules
- Move 'GHCMod.*' to 'GhcMod.Exe'
- Move 'GhcModExe' to 'GhcMod.Exe'

core/GhcMod/World.hs

@@ -0,0 +1,55 @@
+module GhcMod.World where
+
+import GhcMod.GhcPkg
+import GhcMod.PathsAndFiles
+import GhcMod.Types
+import GhcMod.Monad.Types
+import GhcMod.Utils
+
+import Control.Applicative
+import Data.Maybe
+import Data.Traversable hiding (mapM)
+import System.FilePath ((</>))
+
+import GHC.Paths (libdir)
+import Prelude
+
+data World = World {
+    worldPackageCaches :: [TimedFile]
+  , worldCabalFile     :: Maybe TimedFile
+  , worldCabalConfig   :: Maybe TimedFile
+  , worldCabalSandboxConfig :: Maybe TimedFile
+  , worldMappedFiles   :: FileMappingMap
+  } deriving (Eq)
+
+timedPackageCaches :: IOish m => GhcModT m [TimedFile]
+timedPackageCaches = do
+    fs <- mapM (liftIO . mightExist) . map (</> packageCache)
+            =<< getPackageCachePaths libdir
+    (liftIO . timeFile) `mapM` catMaybes fs
+
+getCurrentWorld :: IOish m => GhcModT m World
+getCurrentWorld = do
+    crdl <- cradle
+    pkgCaches    <- timedPackageCaches
+    mCabalFile   <- liftIO $ timeFile `traverse` cradleCabalFile crdl
+    mCabalConfig <- liftIO $ timeMaybe (setupConfigFile crdl)
+    mCabalSandboxConfig <- liftIO $ timeMaybe (sandboxConfigFile crdl)
+    mFileMap     <- getMMappedFiles
+
+    return World {
+        worldPackageCaches = pkgCaches
+      , worldCabalFile     = mCabalFile
+      , worldCabalConfig   = mCabalConfig
+      , worldCabalSandboxConfig = mCabalSandboxConfig
+      , worldMappedFiles   = mFileMap
+      }
+
+didWorldChange :: IOish m => World -> GhcModT m Bool
+didWorldChange world = do
+    (world /=) <$> getCurrentWorld
+
+isYoungerThanSetupConfig :: FilePath -> World -> IO Bool
+isYoungerThanSetupConfig file World {..} = do
+  tfile <- timeFile file
+  return $ worldCabalConfig < Just tfile