construct missing-case witnesses for finite and integer domains

app/Main.hs

@@ -0,0 +1,265 @@
+module Main where
+
+import Control.Exception (SomeException, try)
+import Data.List (foldl', intercalate, isSuffixOf)
+import Data.Maybe (fromMaybe, mapMaybe)
+import qualified Data.Map.Strict as Map
+import Data.Time.Clock (diffUTCTime, getCurrentTime)
+import System.Directory (doesDirectoryExist, listDirectory)
+import System.Environment (getArgs, getProgName)
+import System.Exit (exitFailure, exitSuccess)
+import System.IO (hPutStrLn, stderr)
+
+import Tessera.Analyze
+import Tessera.Check (checkProgram)
+import Tessera.Env (Env, envConstructorTypes)
+import Tessera.Eval
+import Tessera.Graph (renderDot)
+import Tessera.Parser (parseExpression, parseProgram)
+import Tessera.Serialize hiding (renderDiagnostic)
+import Tessera.Syntax
+import Tessera.Tree
+
+main :: IO ()
+main = do
+  arguments <- getArgs
+  case arguments of
+    ("check" : file : rest) -> commandCheck file rest
+    ("explain" : file : rest) -> commandExplain file rest
+    ("compile" : file : rest) -> commandCompile file rest
+    ("run" : file : rest) -> commandRun file rest
+    ("graph" : file : rest) -> commandGraph file rest
+    ("bench" : directory : rest) -> commandBench directory rest
+    _ -> usage
+
+usage :: IO ()
+usage = do
+  name <- getProgName
+  hPutStrLn stderr ("usage: " ++ name ++ " <check|explain|compile|run|graph|bench> ...")
+  exitFailure
+
+optionValue :: String -> [String] -> Maybe String
+optionValue name arguments = case dropWhile (/= name) arguments of
+  (_ : value : _) -> Just value
+  _ -> Nothing
+
+strategyFrom :: [String] -> Strategy
+strategyFrom arguments = case optionValue "--strategy" arguments of
+  Just "heuristic" -> Heuristic
+  _ -> Leftmost
+
+loadProgram :: FilePath -> IO Program
+loadProgram file = do
+  source <- readFile file
+  case parseProgram source of
+    Left diagnostic -> do
+      hPutStrLn stderr (renderDiagnostic diagnostic)
+      exitFailure
+    Right program -> return program
+
+loadEnv :: Program -> IO Env
+loadEnv program = case checkProgram program of
+  Left diagnostic -> do
+    hPutStrLn stderr (renderDiagnostic diagnostic)
+    exitFailure
+  Right env -> return env
+
+renderDiagnostic :: Diagnostic -> String
+renderDiagnostic (Diagnostic span' message) =
+  "line " ++ show (spanLine span') ++ " column " ++ show (spanColumn span') ++ ": " ++ message
+
+renderType :: Type -> String
+renderType ty = case ty of
+  TVar name -> name
+  TName name [] -> name
+  TName name arguments -> name ++ " " ++ unwords (map renderType arguments)
+  TTuple elements -> "(" ++ intercalate ", " (map renderType elements) ++ ")"
+
+renderMatchReport :: MatchReport -> [String]
+renderMatchReport report =
+  [ "match " ++ reportMatchName report
+  , if reportInconclusive report
+      then "  coverage: inconclusive within the configured budget"
+      else if reportExhaustive report
+        then "  coverage: exhaustive"
+        else "  coverage: missing " ++ maybe "" (intercalate ", " . map renderValue) (reportMissingCase report)
+  ]
+  ++ concatMap renderClause (reportClauseReports report)
+  where
+    renderClause clause =
+      let status = case reportClauseStatus clause of
+            ClauseUseful -> "useful"
+            ClauseRedundant -> "redundant"
+          example = case reportClauseExample clause of
+            Just values -> " example " ++ intercalate ", " (map renderValue values)
+            Nothing -> ""
+      in ["  clause " ++ show (reportClauseIndex clause) ++ ": " ++ status ++ example]
+
+commandCheck :: FilePath -> [String] -> IO ()
+commandCheck file _ = do
+  program <- loadProgram file
+  env <- loadEnv program
+  let reports = mapMaybe (analyzeMatch env) program
+      failures = [report | report <- reports, not (reportExhaustive report) || hasRedundant report]
+      output = concatMap renderMatchReport reports
+  mapM_ putStrLn output
+  if null failures then exitSuccess else exitFailure
+  where
+    hasRedundant report = any ((== ClauseRedundant) . reportClauseStatus) (reportClauseReports report)
+
+commandExplain :: FilePath -> [String] -> IO ()
+commandExplain file arguments = do
+  program <- loadProgram file
+  env <- loadEnv program
+  case optionValue "--function" arguments of
+    Nothing -> do
+      hPutStrLn stderr "explain requires --function"
+      exitFailure
+    Just name -> case mapMaybe (analyzeMatch env) program of
+      reports -> case filter ((== name) . reportMatchName) reports of
+        (report : _) -> do
+          mapM_ putStrLn (renderMatchReport report)
+          putStrLn "inhabited types"
+          mapM_ (\(typeName, flag) -> putStrLn ("  " ++ typeName ++ ": " ++ if flag then "inhabited" else "uninhabited")) (Map.toList (reportInhabitedTypes report))
+          exitSuccess
+        [] -> do
+          hPutStrLn stderr ("unknown function " ++ name)
+          exitFailure
+
+commandCompile :: FilePath -> [String] -> IO ()
+commandCompile file arguments = do
+  source <- readFile file
+  program <- case parseProgram source of
+    Left diagnostic -> hPutStrLn stderr (renderDiagnostic diagnostic) >> exitFailure
+    Right p -> return p
+  env <- loadEnv program
+  case optionValue "--function" arguments of
+    Nothing -> hPutStrLn stderr "compile requires --function" >> exitFailure
+    Just name -> case findMatch name program of
+      Nothing -> hPutStrLn stderr ("unknown function " ++ name) >> exitFailure
+      Just match' -> do
+        let strategy = strategyFrom arguments
+            tree = compileMatchFor env strategy match'
+            output = fromMaybe (name ++ ".tree") (optionValue "-o" arguments)
+        writeFile output (encodeArtifact name source strategy tree)
+        putStrLn ("wrote " ++ output ++ " with " ++ strategyName strategy ++ " strategy, " ++ show (treeSize tree) ++ " nodes")
+
+commandRun :: FilePath -> [String] -> IO ()
+commandRun file arguments = do
+  content <- readFile file
+  artifact <- case decodeArtifact content of
+    Left message -> hPutStrLn stderr message >> exitFailure
+    Right a -> return a
+  case optionValue "--function" arguments of
+    Nothing -> hPutStrLn stderr "run requires --function" >> exitFailure
+    Just name -> case findMatch name (artifactProgram artifact) of
+      Nothing -> hPutStrLn stderr ("unknown function " ++ name) >> exitFailure
+      Just match' -> case optionValue "--input" arguments of
+        Nothing -> hPutStrLn stderr "run requires --input" >> exitFailure
+        Just inputFile -> do
+          inputText <- readFile inputFile
+          let arities = Map.toList (Map.map (length . snd) (envConstructorTypes (artifactEnv artifact)))
+          values <- case parseInputs (artifactEnv artifact) arities inputText of
+            Left message -> hPutStrLn stderr message >> exitFailure
+            Right v -> return v
+          results <- mapM (runOne (artifactEnv artifact) match' (artifactTree artifact)) values
+          if and results then exitSuccess else exitFailure
+  where
+    runOne env match' tree values = do
+      let compiled = evaluateCompiled env (matchClauses match') tree values
+          sourceResult = evaluateSource env (matchClauses match') values
+      case (compiled, sourceResult) of
+        (Right a, Right b) -> do
+          putStrLn (intercalate ", " (map renderValue values) ++ " => " ++ renderValue a ++ (if a == b then "" else " (source disagrees: " ++ renderValue b ++ ")"))
+          return (a == b)
+        (Left message, _) -> do
+          putStrLn (intercalate ", " (map renderValue values) ++ " => error " ++ message)
+          return False
+        (_, Left message) -> do
+          putStrLn (intercalate ", " (map renderValue values) ++ " => source error " ++ message)
+          return False
+
+commandGraph :: FilePath -> [String] -> IO ()
+commandGraph file arguments = do
+  content <- readFile file
+  artifact <- case decodeArtifact content of
+    Left message -> hPutStrLn stderr message >> exitFailure
+    Right a -> return a
+  let output = fromMaybe "tree.dot" (optionValue "-o" arguments)
+  writeFile output (renderDot (artifactTree artifact))
+  putStrLn ("wrote " ++ output)
+
+commandBench :: FilePath -> [String] -> IO ()
+commandBench directory arguments = do
+  exists <- doesDirectoryExist directory
+  if not exists
+    then hPutStrLn stderr ("not a directory: " ++ directory) >> exitFailure
+    else do
+      entries <- listDirectory directory
+      let files = [directory ++ "/" ++ entry | entry <- entries, ".tess" `isSuffixOf` entry]
+      mapM_ benchFile files
+  where
+    benchFile file = do
+      program <- loadProgram file
+      env <- loadEnv program
+      let matches = [match' | match' <- program, isMatch match']
+      mapM_ (benchMatch env) matches
+
+    benchMatch env match' = do
+      leftmostStart <- getCurrentTime
+      let leftmostTree = compileMatchFor env Leftmost match'
+      leftmostEnd <- getCurrentTime
+      heuristicStart <- getCurrentTime
+      let heuristicTree = compileMatchFor env Heuristic match'
+      heuristicEnd <- getCurrentTime
+      putStrLn (matchNameOf match')
+      putStrLn ("  leftmost nodes " ++ show (treeSize leftmostTree) ++ " depth " ++ show (treeDepth leftmostTree) ++ " time " ++ show (diffUTCTime leftmostEnd leftmostStart))
+      putStrLn ("  heuristic nodes " ++ show (treeSize heuristicTree) ++ " depth " ++ show (treeDepth heuristicTree) ++ " time " ++ show (diffUTCTime heuristicEnd heuristicStart))
+
+isMatch :: Declaration -> Bool
+isMatch (MatchDeclaration _ _ _ _) = True
+isMatch _ = False
+
+matchNameOf :: Declaration -> String
+matchNameOf (MatchDeclaration name _ _ _) = name
+matchNameOf _ = ""
+
+findMatch :: String -> Program -> Maybe Declaration
+findMatch name program = case [match' | match' <- program, matchNameOf match' == name, isMatch match'] of
+  (match' : _) -> Just match'
+  [] -> Nothing
+
+compileMatchFor :: Env -> Strategy -> Declaration -> Tree
+compileMatchFor env strategy (MatchDeclaration _ arguments _ clauses) =
+  let types = map snd arguments
+      rows = zip (map clausePatterns clauses) [0 .. length clauses - 1]
+  in compileMatch env strategy types rows (initialOccurrences (length arguments))
+compileMatchFor _ _ _ = Failure
+
+parseInputs :: Env -> [(String, Int)] -> String -> Either String [[Value]]
+parseInputs env arities text = go (filter (not . null) (lines text)) []
+  where
+    go [] acc = Right (reverse acc)
+    go (line : rest) acc = case parseInputLine env arities line of
+      Left message -> Left message
+      Right values -> go rest (values : acc)
+
+parseInputLine :: Env -> [(String, Int)] -> String -> Either String [Value]
+parseInputLine env arities line =
+  let pieces = map trim (splitSemicolon line)
+  in mapM parsePiece pieces
+  where
+    parsePiece piece = case parseExpression arities piece of
+      Left diagnostic -> Left ("input parse error: " ++ renderDiagnostic diagnostic)
+      Right expression -> case evalExpr env Map.empty expression of
+        Left message -> Left message
+        Right value -> Right value
+
+trim :: String -> String
+trim = reverse . dropWhile (== ' ') . reverse . dropWhile (== ' ')
+
+splitSemicolon :: String -> [String]
+splitSemicolon [] = [""]
+splitSemicolon text = case break (== ';') text of
+  (piece, []) -> [piece]
+  (piece, _ : rest) -> piece : splitSemicolon rest