{-| Module : Debug.Hoed.Pure Description : Lighweight algorithmic debugging based on observing intermediate values and the cost centre stack. Copyright : (c) 2000 Andy Gill, (c) 2010 University of Kansas, (c) 2013-2015 Maarten Faddegon License : BSD3 Maintainer : hoed@maartenfaddegon.nl Stability : experimental Portability : POSIX Hoed is a tracer and debugger for the programming language Haskell. You can trace a program by annotating functions in suspected modules and linking your program against standard profiling libraries. To locate a defect with Hoed you annotate suspected functions and compile as usual. Then you run your program, information about the annotated functions is collected. Finally you connect to a debugging session using a webbrowser. Let us consider the following program, a defective implementation of a parity function with a test property. > import Test.QuickCheck > > isOdd :: Int -> Bool > isOdd n = isEven (plusOne n) > > isEven :: Int -> Bool > isEven n = mod2 n == 0 > > plusOne :: Int -> Int > plusOne n = n + 1 > > mod2 :: Int -> Int > mod2 n = div n 2 > > prop_isOdd :: Int -> Bool > prop_isOdd x = isOdd (2*x+1) > > main :: IO () > main = printO (prop_isOdd 1) > > main :: IO () > main = quickcheck prop_isOdd Using the property-based test tool QuickCheck we find the counter example `1` for our property. > ./MyProgram > *** Failed! Falsifiable (after 1 test): 1 Hoed can help us determine which function is defective. We annotate the functions `isOdd`, `isEven`, `plusOne` and `mod2` as follows: > import Debug.Hoed.Pure > > isOdd :: Int -> Bool > isOdd = observe "isOdd" isOdd' > isOdd' n = isEven (plusOne n) > > isEven :: Int -> Bool > isEven = observe "isEven" isEven' > isEven' n = mod2 n == 0 > > plusOne :: Int -> Int > plusOne = observe "plusOne" plusOne' > plusOne' n = n + 1 > > mod2 :: Int -> Int > mod2 = observe "mod2" mod2' > mod2' n = div n 2 > > prop_isOdd :: Int -> Bool > prop_isOdd x = isOdd (2*x+1) > > main :: IO () > main = printO (prop_isOdd 1) After running the program a computation tree is constructed and displayed in a web browser. > ./MyProgram > False > Listening on http://127.0.0.1:10000/ After running the program a computation tree is constructed and displayed in a web browser. You can freely browse this tree to get a better understanding of your program. If your program misbehaves, you can judge the computation statements in the tree as 'right' or 'wrong' according to your intention. When enough statements are judged the debugger tells you the location of the fault in your code. <> I work on this debugger in the context of my Ph.D. research. Read more about the theory behind Hoed at . Hoed.Pure is recommended over Hoed.Stk because to debug your program with Hoed.Pure you can optimize your program and do not need to enable profiling. I am keen to hear about your experience with Hoed: where did you find it useful and where would you like to see improvement? You can send me an e-mail at hoed@maartenfaddegon.nl, or use the github issue tracker . -} module Debug.Hoed.Pure ( -- * Basic annotations observe , runO , printO -- * Experimental annotations , traceOnly , doit , observeTempl , observedTypes , observeCC , logO -- * The Observable class , Observer(..) , Observable(..) , (<<) , thunk , nothunk , send , observeBase , observeOpaque , debugO , CDS(..) , Generic ) where import Debug.Hoed.Pure.Observe import Debug.Hoed.Pure.Render import Debug.Hoed.Pure.EventForest import Debug.Hoed.Pure.CompTree import Debug.Hoed.Pure.DemoGUI import Debug.Hoed.Pure.Prop import Prelude hiding (Right) import qualified Prelude import System.IO import Data.Maybe import Control.Monad import Data.List import Data.Ord import Data.Char import System.Environment import System.Directory(createDirectoryIfMissing) import Language.Haskell.TH import GHC.Generics import Data.IORef import System.IO.Unsafe import Data.Graph.Libgraph import Graphics.UI.Threepenny(startGUI,defaultConfig,Config(..)) import System.Directory(createDirectoryIfMissing) -- %************************************************************************ -- %* * -- \subsection{External start functions} -- %* * -- %************************************************************************ -- Run the observe ridden code. -- | run some code and return the Trace debugO :: IO a -> IO Trace debugO program = do { initUniq ; startEventStream ; let errorMsg e = "[Escaping Exception in Code : " ++ show e ++ "]" ; ourCatchAllIO (do { program ; return () }) (hPutStrLn stderr . errorMsg) ; endEventStream } -- | run some code and return the CDS structure (for when you want to write your own debugger). debugO' :: IO a -> IO [CDS] debugO' program = do events <- debugO program return (eventsToCDS events) -- | print a string, with debugging putStrO :: String -> IO () putStrO expr = runO (putStr expr) -- | The main entry point; run some IO code, and debug inside it. -- After the IO action is completed, an algorithmic debugging session is started at -- @http://localhost:10000/@ to which you can connect with your webbrowser. -- -- For example: -- -- @ -- main = runO $ do print (triple 3) -- print (triple 2) -- @ runO :: IO a -> IO () runO program = do (trace,traceInfo,compGraph,frt) <- runO' program debugSession trace traceInfo compGraph frt return () -- | Short for @runO . print@. printO :: (Show a) => a -> IO () printO expr = runO (print expr) -- | Only produces a trace. Useful for performance measurements. traceOnly :: IO a -> IO () traceOnly program = do debugO program return () doit :: IO a -> IO () doit program = do (trace,traceInfo,compGraph,frt) <- runO' program case filter (/= RootVertex) (vertices compGraph) of [] -> return () (v:_) -> do putStrLn "\n=== DoIt ===\n" v' <- judge trace p1 v print v' runO' :: IO a -> IO (Trace,TraceInfo,CompTree,EventForest) runO' program = do createDirectoryIfMissing True ".Hoed/" hPutStrLn stderr "=== program output ===\n" events <- debugO program let cdss = eventsToCDS events let cdss1 = rmEntrySet cdss let cdss2 = simplifyCDSSet cdss1 let eqs = renderCompStmts cdss2 let frt = mkEventForest events rs = filter isRootEvent events ti = traceInfo (reverse events) ds = dependencies ti ct = mkCompTree eqs ds -- hPutStrLn stderr "\n=== Events ===\n" -- hPutStrLn stderr $ unlines (map show . reverse $ events) writeFile ".Hoed/Events" (unlines . map show . reverse $ events) -- hPutStrLn stderr "\n=== Dependencies ===\n" -- hPutStrLn stderr $ unlines (map (\(m,n,msg) -> show m ++ " -> " ++ show n ++ " %" ++ msg) ds) -- hPutStrLn stderr "\n=== Computation Statements ===\n" -- hPutStrLn stderr $ show eqs -- hPutStrLn stderr $ unlines . (map $ show . stmtUIDs) $ eqs hPutStrLn stderr "\n=== Statistics ===\n" let e = length events n = length eqs d = treeDepth ct b = fromIntegral (length . arcs $ ct ) / fromIntegral ((length . vertices $ ct) - (length . leafs $ ct)) hPutStrLn stderr $ "e = " ++ show e hPutStrLn stderr $ "n = " ++ show n hPutStrLn stderr $ "d' = " ++ (show . length $ ds) -- hPutStrLn stderr $ "d = " ++ show d hPutStrLn stderr $ "b = " ++ show b -- hPutStrLn stderr "\n=== Debug Session ===\n" return (events, ti, ct, frt) where summarizeEvent e = show (eventUID e) ++ ": " ++ summarizeChange (change e) summarizeChange (Observe l _ _) = show l summarizeChange (Cons _ c) = show c summarizeChange c = show c showJ (Just s) = show s showJ Nothing = "??" logO :: FilePath -> IO a -> IO () logO filePath program = {- SCC "logO" -} do (_,_,compTree,_) <- runO' program writeFile filePath (showGraph compTree) return () where showGraph g = showWith g showVertex showArc showVertex RootVertex = ("root","") showVertex v = ("\"" ++ (escape . showCompStmt) v ++ "\"", "") showArc _ = "" showCompStmt = show . vertexStmt hPutStrList :: (Show a) => Handle -> [a] -> IO() hPutStrList h [] = hPutStrLn h "" hPutStrList h (c:cs) = do {hPutStrLn h (show c); hPutStrList h cs} ------------------------------------------------------------------------ -- Push mode option handling data PushMode = Vanilla | Drop | Truncate pushMode :: IORef PushMode pushMode = unsafePerformIO $ newIORef Vanilla setPushMode :: PushMode -> IO () setPushMode = writeIORef pushMode getPushMode :: PushMode getPushMode = unsafePerformIO $ readIORef pushMode -- MF TODO: handle a bit nicer? parseArgs :: [String] -> PushMode parseArgs [] = Truncate -- default mode parseArgs (arg:_) = case arg of "--PushVanilla" -> Vanilla "--PushDrop" -> Drop "--PushTruncate" -> Truncate _ -> error ("unknown option " ++ arg) ------------------------------------------------------------------------ -- Algorithmic Debugging debugSession :: Trace -> TraceInfo -> CompTree -> EventForest -> IO () debugSession trace traceInfo tree frt = do createDirectoryIfMissing True ".Hoed/wwwroot/css" treeRef <- newIORef tree startGUI defaultConfig { jsPort = Just 10000 , jsStatic = Just "./.Hoed/wwwroot" } (guiMain trace traceInfo treeRef frt)