Monadify specialise/Specialise: use do, return, standard monad functions and MonadUnique

[ghc-hetmet.git] / compiler / ghci / InteractiveUI.hs

diff --git a/compiler/ghci/InteractiveUI.hs b/compiler/ghci/InteractiveUI.hs
index 8b34e67..2594d13 100644 (file)
--- a/compiler/ghci/InteractiveUI.hs
+++ b/compiler/ghci/InteractiveUI.hs
@@ -54,7 +54,6 @@ import System.Posix hiding (getEnv)
 #else
 import GHC.ConsoleHandler ( flushConsole )
 import qualified System.Win32
-import System.FilePath
 #endif
 
 #ifdef USE_READLINE
@@ -67,6 +66,7 @@ import System.Console.Readline as Readline
 import Control.Exception as Exception
 -- import Control.Concurrent
 
+import System.FilePath
 import qualified Data.ByteString.Char8 as BS
 import Data.List
 import Data.Maybe
@@ -228,15 +228,15 @@ helpText =
  "   :delete *                   delete all breakpoints\n" ++
  "   :force <expr>               print <expr>, forcing unevaluated parts\n" ++
  "   :forward                    go forward in the history (after :back)\n" ++
- "   :history [<n>]              show the last <n> items in the history (after :trace)\n" ++
+ "   :history [<n>]              after :trace, show the execution history\n" ++
  "   :print [<name> ...]         prints a value without forcing its computation\n" ++
  "   :sprint [<name> ...]        simplifed version of :print\n" ++
  "   :step                       single-step after stopping at a breakpoint\n"++
  "   :step <expr>                single-step into <expr>\n"++
- "   :steplocal                  single-step restricted to the current top level decl.\n"++
+ "   :steplocal                  single-step within the current top-level binding\n"++
  "   :stepmodule                 single-step restricted to the current module\n"++
  "   :trace                      trace after stopping at a breakpoint\n"++
- "   :trace <expr>               trace into <expr> (remembers breakpoints for :history)\n"++
+ "   :trace <expr>               evaluate <expr> with tracing on (see :history)\n"++
 
  "\n" ++
  " -- Commands for changing settings:\n" ++
@@ -267,7 +267,8 @@ helpText =
  "   :show modules               show the currently loaded modules\n" ++
  "   :show packages              show the currently active package flags\n" ++
  "   :show languages             show the currently active language flags\n" ++
- "   :show <setting>             show anything that can be set with :set (e.g. args)\n" ++
+ "   :show <setting>             show value of <setting>, which is one of\n" ++
+ "                                  [args, prog, prompt, editor, stop]\n" ++
  "\n" 
 
 findEditor :: IO String
@@ -355,36 +356,43 @@ interactiveUI session srcs maybe_exprs = do
 
 runGHCi :: [(FilePath, Maybe Phase)] -> Maybe [String] -> GHCi ()
 runGHCi paths maybe_exprs = do
-  let read_dot_files = not opt_IgnoreDotGhci
+  let 
+   read_dot_files = not opt_IgnoreDotGhci
 
-  when (read_dot_files) $ do
-    -- Read in ./.ghci.
-    let file = "./.ghci"
-    exists <- io (doesFileExist file)
-    when exists $ do
-       dir_ok  <- io (checkPerms ".")
-       file_ok <- io (checkPerms file)
+   current_dir = return (Just ".ghci")
+
+   app_user_dir = do
+    either_dir <- io $ IO.try (getAppUserDataDirectory "ghc")
+    case either_dir of
+      Right dir -> return (Just (dir </> "ghci.conf"))
+      _ -> return Nothing
+
+   home_dir = do
+    either_dir <- io $ IO.try (getEnv "HOME")
+    case either_dir of
+      Right home -> return (Just (home </> ".ghci"))
+      _ -> return Nothing
+
+   sourceConfigFile :: FilePath -> GHCi ()
+   sourceConfigFile file = do
+     exists <- io $ doesFileExist file
+     when exists $ do
+       dir_ok  <- io $ checkPerms (getDirectory file)
+       file_ok <- io $ checkPerms file
        when (dir_ok && file_ok) $ do
-          either_hdl <- io (IO.try (openFile "./.ghci" ReadMode))
-          case either_hdl of
-             Left _e   -> return ()
-             Right hdl -> runCommands (fileLoop hdl False False)
+         either_hdl <- io $ IO.try (openFile file ReadMode)
+         case either_hdl of
+           Left _e   -> return ()
+           Right hdl -> runCommands (fileLoop hdl False False)
+     where
+      getDirectory f = case takeDirectory f of "" -> "."; d -> d
 
   when (read_dot_files) $ do
-    -- Read in $HOME/.ghci
-    either_dir <- io (IO.try getHomeDirectory)
-    case either_dir of
-       Left _e -> return ()
-       Right dir -> do
-          cwd <- io (getCurrentDirectory)
-          when (dir /= cwd) $ do
-             let file = dir ++ "/.ghci"
-             ok <- io (checkPerms file)
-             when ok $ do
-               either_hdl <- io (IO.try (openFile file ReadMode))
-               case either_hdl of
-                  Left _e   -> return ()
-                  Right hdl -> runCommands (fileLoop hdl False False)
+    cfgs0 <- sequence [ current_dir, app_user_dir, home_dir ]
+    cfgs <- io $ mapM canonicalizePath (catMaybes cfgs0)
+    mapM_ sourceConfigFile (nub cfgs)
+        -- nub, because we don't want to read .ghci twice if the
+        -- CWD is $HOME.
 
   -- Perform a :load for files given on the GHCi command line
   -- When in -e mode, if the load fails then we want to stop
@@ -1557,7 +1565,8 @@ showCmd str = do
         ["context"]  -> showContext
         ["packages"]  -> showPackages
         ["languages"]  -> showLanguages
-       _ -> throwDyn (CmdLineError "syntax:  :show [args|prog|prompt|editor|stop|modules|bindings|breaks|context]")
+       _ -> throwDyn (CmdLineError ("syntax:  :show [ args | prog | prompt | editor | stop | modules | bindings\n"++
+                                     "               | breaks | context | packages | languages ]"))
 
 showModules :: GHCi ()
 showModules = do