+historyCmd :: String -> GHCi ()
+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)..]
+ let names = map GHC.historyEnclosingDecl took
+ printForUser (vcat(zipWith3
+ (\x y z -> x <+> y <+> z)
+ (map text nums)
+ (map (bold . ppr) names)
+ (map (parens . ppr) spans)))
+ io $ putStrLn $ if null rest then "<end of history>" else "..."
+
+bold c | do_bold = text start_bold <> c <> text end_bold
+ | otherwise = c
+
+backCmd :: String -> GHCi ()
+backCmd = noArgs $ do
+ s <- getSession
+ (names, ix, span) <- io $ GHC.back s
+ printForUser $ ptext SLIT("Logged breakpoint at") <+> ppr span
+ printTypeOfNames s names
+ -- run the command set with ":set stop <cmd>"
+ st <- getGHCiState
+ enqueueCommands [stop st]
+
+forwardCmd :: String -> GHCi ()
+forwardCmd = noArgs $ do
+ s <- getSession
+ (names, ix, span) <- io $ GHC.forward s
+ printForUser $ (if (ix == 0)
+ then ptext SLIT("Stopped at")
+ else ptext SLIT("Logged breakpoint at")) <+> ppr span
+ printTypeOfNames s names
+ -- run the command set with ":set stop <cmd>"
+ st <- getGHCiState
+ enqueueCommands [stop st]
+