fix panic in #1379

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

diff --git a/compiler/ghci/InteractiveUI.hs b/compiler/ghci/InteractiveUI.hs
index 3bda8bd..ca8c050 100644 (file)
--- a/compiler/ghci/InteractiveUI.hs
+++ b/compiler/ghci/InteractiveUI.hs
@@ -155,7 +155,7 @@ helpText =
  "   :add <filename> ...         add module(s) to the current target set\n" ++
  "   :browse [*]<module>         display the names defined by <module>\n" ++
  "   :cd <dir>                   change directory to <dir>\n" ++
- "   :cmd <expr>                 run the commands returned by <expr>::IO String"++
+ "   :cmd <expr>                 run the commands returned by <expr>::IO String\n" ++
  "   :ctags [<file>]             create tags file for Vi (default: \"tags\")\n" ++
  "   :def <cmd> <expr>           define a command :<cmd>\n" ++
  "   :edit <file>                edit file\n" ++
@@ -722,25 +722,47 @@ changeDirectory dir = do
   io (setCurrentDirectory dir)
 
 editFile :: String -> GHCi ()
-editFile str
-  | null str  = do
-       -- find the name of the "topmost" file loaded
-     session <- getSession
-     graph0 <- io (GHC.getModuleGraph session)
-     graph1 <- filterM (io . GHC.isLoaded session . GHC.ms_mod_name) graph0
-     let graph2 = flattenSCCs (GHC.topSortModuleGraph True graph1 Nothing)
-     case GHC.ml_hs_file (GHC.ms_location (last graph2)) of
-       Just file -> do_edit file
-       Nothing   -> throwDyn (CmdLineError "unknown file name")
-  | otherwise = do_edit str
-  where
-       do_edit file = do
-          st <- getGHCiState
-          let cmd = editor st
-          when (null cmd) $ 
-               throwDyn (CmdLineError "editor not set, use :set editor")
-          io $ system (cmd ++ ' ':file)
-           return ()
+editFile str =
+  do file <- if null str then chooseEditFile else return str
+     st <- getGHCiState
+     let cmd = editor st
+     when (null cmd) 
+       $ throwDyn (CmdLineError "editor not set, use :set editor")
+     io $ system (cmd ++ ' ':file)
+     return ()
+
+-- The user didn't specify a file so we pick one for them.
+-- Our strategy is to pick the first module that failed to load,
+-- or otherwise the first target.
+--
+-- XXX: Can we figure out what happened if the depndecy analysis fails
+--      (e.g., because the porgrammeer mistyped the name of a module)?
+-- XXX: Can we figure out the location of an error to pass to the editor?
+-- XXX: if we could figure out the list of errors that occured during the
+-- last load/reaload, then we could start the editor focused on the first
+-- of those.
+chooseEditFile :: GHCi String
+chooseEditFile =
+  do session <- getSession
+     let hasFailed x = io $ fmap not $ GHC.isLoaded session $ GHC.ms_mod_name x
+
+     graph <- io (GHC.getModuleGraph session)
+     failed_graph <- filterM hasFailed graph
+     let order g  = flattenSCCs $ GHC.topSortModuleGraph True g Nothing
+         pick xs  = case xs of
+                      x : _ -> GHC.ml_hs_file (GHC.ms_location x)
+                      _     -> Nothing
+
+     case pick (order failed_graph) of
+       Just file -> return file
+       Nothing   -> 
+         do targets <- io (GHC.getTargets session)
+            case msum (map fromTarget targets) of
+              Just file -> return file
+              Nothing   -> throwDyn (CmdLineError "No files to edit.")
+          
+  where fromTarget (GHC.Target (GHC.TargetFile f _) _) = Just f
+        fromTarget _ = Nothing -- when would we get a module target?
 
 defineMacro :: String -> GHCi ()
 defineMacro s = do
@@ -845,17 +867,12 @@ checkModule m = do
   afterLoad (successIf (isJust result)) session
 
 reloadModule :: String -> GHCi ()
-reloadModule "" = do
-  io (revertCAFs)              -- always revert CAFs on reload.
-  discardActiveBreakPoints
-  session <- getSession
-  doLoad session LoadAllTargets
-  return ()
 reloadModule m = do
   io (revertCAFs)              -- always revert CAFs on reload.
   discardActiveBreakPoints
   session <- getSession
-  doLoad session (LoadUpTo (GHC.mkModuleName m))
+  doLoad session $ if null m then LoadAllTargets 
+                             else LoadUpTo (GHC.mkModuleName m)
   return ()
 
 doLoad session howmuch = do
@@ -1454,6 +1471,10 @@ wantNameFromInterpretedModule noCanDo str and_then = do
       []    -> return ()
       (n:_) -> do
             let modl = GHC.nameModule n
+            if not (GHC.isExternalName n)
+               then noCanDo n $ ppr n <>
+                                text " is not defined in an interpreted module"
+               else do
             is_interpreted <- io (GHC.moduleIsInterpreted session modl)
             if not is_interpreted
                then noCanDo n $ text "module " <> ppr modl <>
@@ -1775,7 +1796,8 @@ listModuleLine modl line = do
 -- If the highlight flag is True, also highlight the span using
 -- start_bold/end_bold.
 listAround span do_highlight = do
-      contents <- BS.readFile (unpackFS file)
+      pwd      <- getEnv "PWD" 
+      contents <- BS.readFile (pwd `joinFileName` unpackFS file)
       let 
           lines = BS.split '\n' contents
           these_lines = take (line2 - line1 + 1 + pad_before + pad_after) $