Avoid loading prelude from the default path

We now bundle the whole source in the compiler binary anyway, so it's
faster to just use that. Additionally, this should allow us to easily
install the `dex` binary without having to carry the `prelude.dx` file
around. The change is not that simple, because it required an update to
the caching mechanism, which now also uses global XDG directories.

1 files changed, 15 insertions, 8 deletions

diff --git a/src/dex.hs b/src/dex.hs
index 9e6c9435..198099c9 100644
--- a/src/dex.hs
+++ b/src/dex.hs
@@ -13,11 +13,13 @@ import Options.Applicative
 import System.Posix.Terminal (queryTerminal)
 import System.Posix.IO (stdOutput)
 import System.Exit
+import System.Directory
 
 import Syntax
 import PPrint
 import RenderHtml
 import Serialize
+import Resources
 
 import TopLevel
 import Parser  hiding (Parser)
@@ -29,11 +31,14 @@ data EvalMode = ReplMode String
               | WebMode    FilePath
               | WatchMode  FilePath
               | ScriptMode FilePath DocFmt ErrorHandling
-data CmdOpts = CmdOpts EvalMode FilePath EvalConfig Backend
+data CmdOpts = CmdOpts EvalMode (Maybe FilePath) EvalConfig Backend
 
-runMode :: EvalMode -> FilePath -> EvalConfig -> IO ()
+runMode :: EvalMode -> (Maybe FilePath) -> EvalConfig -> IO ()
 runMode evalMode preludeFile opts = do
-  env <- memoizeFileEval "prelude.cache" (evalPrelude opts) preludeFile
+  key <- case preludeFile of
+           Nothing   -> return ""  -- memoizeFileEval already checks compiler version
+           Just path -> show <$> getModificationTime path
+  env <- cached "prelude" key $ evalPrelude opts preludeFile
   let runEnv m = evalStateT m env
   case evalMode of
     ReplMode prompt ->
@@ -46,9 +51,12 @@ runMode evalMode preludeFile opts = do
     WebMode   fname -> runWeb      fname opts env
     WatchMode fname -> runTerminal fname opts env
 
-evalPrelude :: EvalConfig -> FilePath -> IO TopEnv
+evalPrelude :: EvalConfig -> (Maybe FilePath) -> IO TopEnv
 evalPrelude opts fname = flip execStateT mempty $ do
-  result <- evalFile opts fname
+  source <- case fname of
+              Nothing   -> return $ preludeSource
+              Just path -> liftIO $ readFile path
+  result <- evalSource opts source
   void $ liftErrIO $ mapM (\(_, Result _ r) -> r) result
 
 liftErrIO :: MonadIO m => Except a -> m a
@@ -132,9 +140,8 @@ parseEvalOpts = EvalConfig
   <*> pure (error "Backend not initialized")
   <*> pure (error "Logging not initialized")
 
-parsePreludeFile :: Parser FilePath
-parsePreludeFile = (strOption $ long "prelude" <> value "prelude.dx" <> metavar "FILE"
-                                               <> help "Prelude file" <> showDefault)
+parsePreludeFile :: Parser (Maybe FilePath)
+parsePreludeFile = optional $ strOption $ long "prelude" <> metavar "FILE" <> help "Prelude file"
 
 parseBackend :: Parser Backend
 parseBackend =