let you :show things that you can :set (e.g. args, prog etc.)

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

diff --git a/compiler/ghci/InteractiveUI.hs b/compiler/ghci/InteractiveUI.hs
index 9b0bdf9..3a76f92 100644 (file)
--- a/compiler/ghci/InteractiveUI.hs
+++ b/compiler/ghci/InteractiveUI.hs
@@ -74,6 +74,7 @@ import Data.Char
 import Data.Dynamic
 import Data.Array
 import Control.Monad as Monad
+import Text.Printf
 
 import Foreign.StablePtr       ( newStablePtr )
 import GHC.Exts                ( unsafeCoerce# )
@@ -539,7 +540,7 @@ runStmt stmt step
       result <- io $ withProgName (progname st) $ withArgs (args st) $
                     GHC.runStmt session stmt step
       afterRunStmt result
-      return False
+      return (isRunResultOk result)
 
 
 afterRunStmt :: GHC.RunResult -> GHCi (Maybe (Bool,[Name]))
@@ -583,6 +584,11 @@ switchOnRunResult (GHC.RunBreak threadId names info) = do
    return (Just (True,names))
 
 
+isRunResultOk :: GHC.RunResult -> Bool
+isRunResultOk (GHC.RunOk _) = True
+isRunResultOk _             = False
+
+
 showTypeOfName :: Session -> Name -> GHCi ()
 showTypeOfName session n
    = do maybe_tything <- io (GHC.lookupName session n)
@@ -1148,14 +1154,20 @@ optToStr RevertCAFs = "r"
 -- ---------------------------------------------------------------------------
 -- code for `:show'
 
-showCmd str =
+showCmd str = do
+  st <- getGHCiState
   case words str of
+        ["args"]     -> io $ putStrLn (show (args st))
+        ["prog"]     -> io $ putStrLn (show (progname st))
+        ["prompt"]   -> io $ putStrLn (show (prompt st))
+        ["editor"]   -> io $ putStrLn (show (editor st))
+        ["stop"]     -> io $ putStrLn (show (stop st))
        ["modules" ] -> showModules
        ["bindings"] -> showBindings
        ["linker"]   -> io showLinkerState
-        ["breaks"] -> showBkptTable
-        ["context"] -> showContext
-       _ -> throwDyn (CmdLineError "syntax:  :show [modules|bindings|breaks]")
+        ["breaks"]   -> showBkptTable
+        ["context"]  -> showContext
+       _ -> throwDyn (CmdLineError "syntax:  :show [args|prog|prompt|editor|stop|modules|bindings|breaks|context]")
 
 showModules = do
   session <- getSession
@@ -1479,15 +1491,23 @@ deleteCmd argLine = do
          | otherwise = return ()
 
 historyCmd :: String -> GHCi ()
-historyCmd = noArgs $ do
-  s <- getSession
-  resumes <- io $ GHC.getResumeContext s
-  case resumes of
-    [] -> io $ putStrLn "Not stopped at a breakpoint"
-    (r:rs) -> do
-      let hist = GHC.resumeHistory r
-      spans <- mapM (io . GHC.getHistorySpan s) hist
-      printForUser (vcat (map ppr spans))
+historyCmd arg
+  | null arg        = history 20
+  | all isDigit arg = history (read arg)
+  | otherwise       = io $ putStrLn "Syntax:  :history [num]"
+  where
+  history num = do
+    s <- getSession
+    resumes <- io $ GHC.getResumeContext s
+    case resumes of
+      [] -> io $ putStrLn "Not stopped at a breakpoint"
+      (r:rs) -> do
+        let hist = GHC.resumeHistory r
+            (took,rest) = splitAt num hist
+        spans <- mapM (io . GHC.getHistorySpan s) took
+        let nums = map (printf "-%-3d:") [(1::Int)..]
+        printForUser (vcat (zipWith (<+>) (map text nums) (map ppr spans)))
+        io $ putStrLn $ if null rest then "<end of history>" else "..."
 
 backCmd :: String -> GHCi ()
 backCmd = noArgs $ do