Clean up and list SKI conversion fix

src/Eval.hs

@@ -62,27 +62,39 @@ evalAST env term
 elimLambda :: TricuAST -> TricuAST
 elimLambda = go
   where
-    -- η-reduction
+    go term
-    go (SLambda [v] (SApp f (SVar x)))
+      | etaReduction term   = elimLambda $ etaReduceResult term
-      | v == x && not (isFree v f) = elimLambda f
+      | triagePattern term  = _TRI
-    -- Triage optimization
+      | composePattern term = _B
-    go (SLambda [a] (SLambda [b] (SLambda [c] body)))
+      | lambdaList term     = elimLambda $ lambdaListResult term
-      | body == triageBody         = _TRIAGE
+      | nestedLambda term   = nestedLambdaResult term
-      where
+      | application term    = applicationResult term
-        triageBody =
+      | otherwise           = term
-          SApp (SApp TLeaf (SApp (SApp TLeaf (SVar a)) (SVar b))) (SVar c)
+
-    -- Composition optimization
+    etaReduction (SLambda [v] (SApp f (SVar x))) = v == x && not (isFree v f)
-    go (SLambda [f] (SLambda [g] (SLambda [x] body)))
+    etaReduction _ = False
-      | body == SApp (SVar f) (SApp (SVar g) (SVar x)) = _B
+    etaReduceResult (SLambda [_] (SApp f _)) = f
-    -- General elimination
+
-    go (SLambda [v] (SList xs))
+    triagePattern (SLambda [a] (SLambda [b] (SLambda [c] body))) = body == triageBody a b c
-      = elimLambda (SLambda [v] (foldr wrapTLeaf TLeaf xs))
+    triagePattern _ = False
-        where wrapTLeaf m r = SApp (SApp TLeaf m) r
+
-    go (SLambda (v:vs) body)
+    composePattern (SLambda [f] (SLambda [g] (SLambda [x] body))) = body == composeBody f g x
-      | null vs                    = toSKI v (elimLambda body)
+    composePattern _ = False
-      | otherwise                  = elimLambda (SLambda [v] (SLambda vs body))
+
-    go (SApp f g)                  = SApp (elimLambda f) (elimLambda g)
+    lambdaList (SLambda [_] (SList _)) = True
-    go x                           = x
+    lambdaList _ = False
+    lambdaListResult (SLambda [v] (SList xs)) = SLambda [v] (foldr wrapTLeaf TLeaf xs)
+    wrapTLeaf m r = SApp (SApp TLeaf m) r
+
+    nestedLambda (SLambda (_:_) _) = True
+    nestedLambda _ = False
+    nestedLambdaResult (SLambda (v:vs) body)
+      | null vs   = toSKI v (elimLambda body)
+      | otherwise = elimLambda (SLambda [v] (SLambda vs body))
+
+    application (SApp _ _) = True
+    application _ = False
+    applicationResult (SApp f g) = SApp (elimLambda f) (elimLambda g)
 
     toSKI x (SVar y)
       | x == y           = _I
@@ -90,30 +102,38 @@ elimLambda = go
     toSKI x t@(SApp n u)
       | not (isFree x t) = SApp _K t
       | otherwise        = SApp (SApp _S (toSKI x n)) (toSKI x u)
+    toSKI x (SList xs)
+      | not (isFree x (SList xs)) = SApp _K (SList xs)
+      | otherwise = SList (map (toSKI x) xs)
     toSKI x t
       | not (isFree x t) = SApp _K t
       | otherwise        = errorWithoutStackTrace "Unhandled toSKI conversion"
 
-    _S       = parseSingle "t (t (t t t)) t"
+    -- Combinators and special forms
-    _K       = parseSingle "t t"
+    _S   = parseSingle "t (t (t t t)) t"
-    _I       = parseSingle "t (t (t t)) t"
+    _K   = parseSingle "t t"
-    _B       = parseSingle "t (t (t t (t (t (t t t)) t))) (t t)"
+    _I   = parseSingle "t (t (t t)) t"
-    _TRIAGE  = parseSingle "t (t (t t (t (t (t t t))))) t"
+    _B   = parseSingle "t (t (t t (t (t (t t t)) t))) (t t)"
+    _TRI = parseSingle "t (t (t t (t (t (t t t))))) t"
+    
+    -- Pattern bodies
+    triageBody a b c = SApp (SApp TLeaf (SApp (SApp TLeaf (SVar a)) (SVar b))) (SVar c)
+    composeBody f g x = SApp (SVar f) (SApp (SVar g) (SVar x))
 
 isFree :: String -> TricuAST -> Bool
 isFree x = Set.member x . freeVars
 
 freeVars :: TricuAST -> Set.Set String
 freeVars (SVar    v    ) = Set.singleton v
-freeVars (SInt    _    ) = Set.empty
-freeVars (SStr    _    ) = Set.empty
 freeVars (SList   s    ) = foldMap freeVars s
+freeVars (SLambda v b  ) = foldr Set.delete (freeVars b) v
 freeVars (SApp    f a  ) = freeVars f <> freeVars a
-freeVars  TLeaf          = Set.empty
+freeVars (TFork   l r  ) = freeVars l <> freeVars r
 freeVars (SDef   _ _ b)  = freeVars b
 freeVars (TStem   t    ) = freeVars t
-freeVars (TFork   l r  ) = freeVars l <> freeVars r
+freeVars (SInt    _    ) = Set.empty
-freeVars (SLambda v b  ) = foldr Set.delete (freeVars b) v
+freeVars (SStr    _    ) = Set.empty
+freeVars  TLeaf          = Set.empty
 freeVars  _              = Set.empty
 
 reorderDefs :: Env -> [TricuAST] -> [TricuAST]
@@ -131,7 +151,7 @@ reorderDefs env defs
     graph = buildDepGraph defsOnly
     sortedDefs = sortDeps graph
     defMap = Map.fromList [(name, def) | def@(SDef name _ _) <- defsOnly]
-    orderedDefs = map (\name -> defMap Map.! name) sortedDefs
+    orderedDefs = map (defMap Map.!) sortedDefs
 
     freeVarsDefs = foldMap snd defsWithFreeVars
     freeVarsOthers = foldMap freeVars others
@@ -139,8 +159,8 @@ reorderDefs env defs
     validNames = Set.fromList defNames `Set.union` Set.fromList (Map.keys env)
     missingDeps = Set.toList (allFreeVars `Set.difference` validNames)
 
-    isDef (SDef _ _ _) = True
+    isDef SDef {} = True
-    isDef _            = False
+    isDef _       = False
 
 buildDepGraph :: [TricuAST] -> Map.Map String (Set.Set String)
 buildDepGraph topDefs

src/Main.hs

@@ -63,18 +63,17 @@ main = do
   case args of
     Repl -> do
       putStrLn "Welcome to the tricu REPL"
-      putStrLn "You can exit with `CTRL+D` or the `!exit` command.`"
+      putStrLn "You may exit with `CTRL+D` or the `!exit` command."
+      putStrLn "Try typing `!` with tab completion for more commands."
       repl Map.empty
     Evaluate { file = filePaths, form = form } -> do
       result <- case filePaths of
-        [] -> do
+        [] -> runTricuT <$> getContents
-          t <- getContents
-          pure $ runTricu t
         (filePath:restFilePaths) -> do
             initialEnv <- evaluateFile filePath
             finalEnv <- foldM evaluateFileWithContext initialEnv restFilePaths
             pure $ mainResult finalEnv
-      let fRes = formatResult form result
+      let fRes = formatT form result
       putStr fRes
     TDecode { file = filePaths } -> do
       value <- case filePaths of
@@ -82,8 +81,48 @@ main = do
         (filePath:_) -> readFile filePath
       putStrLn $ decodeResult $ result $ evalTricu Map.empty $ parseTricu value
 
-runTricu :: String -> T
+-- Simple interfaces
-runTricu input =
+
+runTricu :: String -> String
+runTricu = formatT TreeCalculus . runTricuT
+
+runTricuT :: String -> T
+runTricuT input =
   let asts     = parseTricu input
       finalEnv = evalTricu Map.empty asts
    in result finalEnv
+
+runTricuEnv :: Env -> String -> String
+runTricuEnv env = formatT TreeCalculus . runTricuTEnv env
+
+runTricuTEnv :: Env -> String -> T
+runTricuTEnv env input =
+  let asts     = parseTricu input
+      finalEnv = evalTricu env asts
+   in result finalEnv
+
+runTricuWithEnvT :: String -> (Env, T)
+runTricuWithEnvT input =
+  let asts     = parseTricu input
+      finalEnv = evalTricu Map.empty asts
+   in (finalEnv, result finalEnv)
+
+runTricuWithEnv :: String -> (Env, String)
+runTricuWithEnv input =
+  let asts     = parseTricu input
+      finalEnv = evalTricu Map.empty asts
+      res      = result finalEnv
+   in (finalEnv, formatT TreeCalculus res)
+
+runTricuEnvWithEnvT :: Env -> String -> (Env, T)
+runTricuEnvWithEnvT env input =
+  let asts     = parseTricu input
+      finalEnv = evalTricu env asts
+   in (finalEnv, result finalEnv)
+
+runTricuEnvWithEnv :: Env -> String -> (Env, String)
+runTricuEnvWithEnv env input =
+  let asts     = parseTricu input
+      finalEnv = evalTricu env asts
+      res      = result finalEnv
+   in (finalEnv, formatT TreeCalculus res)

src/REPL.hs

@@ -152,7 +152,7 @@ repl env = runInputT settings (withInterrupt (loop env Decode))
           newEnv = evalTricu env asts
       case Map.lookup "!result" newEnv of
         Just r -> do
-          putStrLn $ "tricu > " ++ formatResult form r
+          putStrLn $ "tricu > " ++ formatT form r
         Nothing -> pure ()
       return newEnv
 
@@ -182,7 +182,7 @@ repl env = runInputT settings (withInterrupt (loop env Decode))
           liftIO $ writeFile filepath ""
           outputStrLn "File created..."
           forM_ definitions $ \(name, value) -> do
-            let content = name ++ " = " ++ formatResult TreeCalculus value ++ "\n"
+            let content = name ++ " = " ++ formatT TreeCalculus value ++ "\n"
             outputStrLn $ "Writing definition: " ++ name ++ " with length " ++ show (length content)
             liftIO $ appendFile filepath content
           outputStrLn $ "Saved " ++ show (length definitions) ++ " definitions to " ++ p

src/Research.hs

@@ -15,7 +15,7 @@ data T = Leaf | Stem T | Fork T T
 -- Abstract Syntax Tree for tricu
 data TricuAST
   = SVar String
-  | SInt Int
+  | SInt Integer
   | SStr String
   | SList [TricuAST]
   | SDef String [String] TricuAST
@@ -33,7 +33,7 @@ data LToken
   = LKeywordT
   | LIdentifier String
   | LNamespace String
-  | LIntegerLiteral Int
+  | LIntegerLiteral Integer
   | LStringLiteral String
   | LAssign
   | LColon
@@ -84,9 +84,9 @@ _not = Fork (Fork _true (Fork Leaf _false)) Leaf
 
 -- Marshalling
 ofString :: String -> T
-ofString str = ofList $ map (ofNumber . fromEnum) str
+ofString str = ofList $ map (ofNumber . toInteger . fromEnum) str
 
-ofNumber :: Int -> T
+ofNumber :: Integer -> T
 ofNumber 0 = Leaf
 ofNumber n =
   Fork
@@ -96,7 +96,7 @@ ofNumber n =
 ofList :: [T] -> T
 ofList = foldr Fork Leaf
 
-toNumber :: T -> Either String Int
+toNumber :: T -> Either String Integer
 toNumber Leaf = Right 0
 toNumber (Fork Leaf rest) = case toNumber rest of
   Right n -> Right (2 * n)
@@ -108,7 +108,7 @@ toNumber _ = Left "Invalid Tree Calculus number"
 
 toString :: T -> Either String String
 toString tc = case toList tc of
-  Right list -> traverse (fmap toEnum . toNumber) list
+  Right list -> traverse (fmap (toEnum . fromInteger) . toNumber) list
   Left err -> Left "Invalid Tree Calculus string"
 
 toList :: T -> Either String [T]
@@ -119,13 +119,13 @@ toList (Fork x rest) = case toList rest of
 toList _ = Left "Invalid Tree Calculus list"
 
 -- Outputs
-formatResult :: EvaluatedForm -> T -> String
+formatT :: EvaluatedForm -> T -> String
-formatResult TreeCalculus = toSimpleT . show
+formatT TreeCalculus = toSimpleT . show
-formatResult FSL          = show
+formatT FSL          = show
-formatResult AST          = show . toAST
+formatT AST          = show . toAST
-formatResult Ternary      = toTernaryString
+formatT Ternary      = toTernaryString
-formatResult Ascii        = toAscii
+formatT Ascii        = toAscii
-formatResult Decode       = decodeResult
+formatT Decode       = decodeResult
 
 toSimpleT :: String -> String
 toSimpleT s = T.unpack
@@ -166,7 +166,7 @@ decodeResult tc =
     (_, _, Right n) -> show n
     (_, Right xs@(_:_), _) -> "[" ++ intercalate ", " (map decodeResult xs) ++ "]"
     (_, Right [], _) -> "[]"
-    _ -> formatResult TreeCalculus tc
+    _ -> formatT TreeCalculus tc
   where
     isCommonChar c =
       let n = fromEnum c

test/Spec.hs

@@ -21,8 +21,8 @@ import qualified Data.Set as Set
 main :: IO ()
 main = defaultMain tests
 
-runTricu :: String -> String
+tricuTestString :: String -> String
-runTricu s = show $ result (evalTricu Map.empty $ parseTricu s)
+tricuTestString s = show $ result (evalTricu Map.empty $ parseTricu s)
 
 tests :: TestTree
 tests = testGroup "Tricu Tests"
@@ -266,7 +266,7 @@ simpleEvaluation = testGroup "Evaluation Tests"
   , testCase "Immutable definitions" $ do
       let input = "x = t t\nx = t\nx"
           env = evalTricu Map.empty (parseTricu input)
-      result <- try (evaluate (runTricu input)) :: IO (Either SomeException String)
+      result <- try (evaluate (tricuTestString input)) :: IO (Either SomeException String)
       case result of
         Left  _ -> return ()
         Right _ -> assertFailure "Expected evaluation error"
@@ -283,84 +283,84 @@ lambdas :: TestTree
 lambdas = testGroup "Lambda Evaluation Tests"
   [ testCase "Lambda Identity Function" $ do
       let input = "id = (x : x)\nid t"
-      runTricu input @?= "Leaf"
+      tricuTestString input @?= "Leaf"
 
   , testCase "Lambda Constant Function (K combinator)" $ do
       let input = "k = (x y : x)\nk t (t t)"
-      runTricu input @?= "Leaf"
+      tricuTestString input @?= "Leaf"
 
   , testCase "Lambda Application with Variable" $ do
       let input = "id = (x : x)\nval = t t\nid val"
-      runTricu input @?= "Stem Leaf"
+      tricuTestString input @?= "Stem Leaf"
 
   , testCase "Lambda Application with Multiple Arguments" $ do
       let input = "apply = (f x y : f x y)\nk = (a b : a)\napply k t (t t)"
-      runTricu input @?= "Leaf"
+      tricuTestString input @?= "Leaf"
 
    , testCase "Nested Lambda Application" $ do
       let input = "apply = (f x y : f x y)\nid = (x : x)\napply (f x : f x) id t"
-      runTricu input @?= "Leaf"
+      tricuTestString input @?= "Leaf"
 
   , testCase "Lambda with a complex body" $ do
       let input = "f = (x : t (t x))\nf t"
-      runTricu input @?= "Stem (Stem Leaf)"
+      tricuTestString input @?= "Stem (Stem Leaf)"
 
   , testCase "Lambda returning a function" $ do
       let input = "f = (x : (y : x))\ng = f t\ng (t t)"
-      runTricu input @?= "Leaf"
+      tricuTestString input @?= "Leaf"
 
   , testCase "Lambda with Shadowing" $ do
       let input = "f = (x : (x : x))\nf t (t t)"
-      runTricu input @?= "Stem Leaf"
+      tricuTestString input @?= "Stem Leaf"
 
    , testCase "Lambda returning another lambda" $ do
       let input = "k = (x : (y : x))\nk_app = k t\nk_app (t t)"
-      runTricu input @?= "Leaf"
+      tricuTestString input @?= "Leaf"
 
    , testCase "Lambda with free variables" $ do
       let input = "y = t t\nf = (x : y)\nf t"
-      runTricu input @?= "Stem Leaf"
+      tricuTestString input @?= "Stem Leaf"
 
    , testCase "SKI Composition" $ do
       let input = "s = (x y z : x z (y z))\nk = (x y : x)\ni = (x : x)\ncomp = s k i\ncomp t (t t)"
-      runTricu input @?= "Stem (Stem Leaf)"
+      tricuTestString input @?= "Stem (Stem Leaf)"
 
    , testCase "Lambda with multiple parameters and application" $ do
       let input = "f = (a b c : t a b c)\nf t (t t) (t t t)"
-      runTricu input @?= "Stem Leaf"
+      tricuTestString input @?= "Stem Leaf"
 
    , testCase "Lambda with nested application in the body" $ do
       let input = "f = (x : t (t (t x)))\nf t"
-      runTricu input @?= "Stem (Stem (Stem Leaf))"
+      tricuTestString input @?= "Stem (Stem (Stem Leaf))"
 
     , testCase "Lambda returning a function and applying it" $ do
         let input = "f = (x : (y : t x y))\ng = f t\ng (t t)"
-        runTricu input @?= "Fork Leaf (Stem Leaf)"
+        tricuTestString input @?= "Fork Leaf (Stem Leaf)"
 
     , testCase "Lambda applying a variable" $ do
         let input = "id = (x : x)\na = t t\nid a"
-        runTricu input @?= "Stem Leaf"
+        tricuTestString input @?= "Stem Leaf"
 
     , testCase "Nested lambda abstractions in the same expression" $ do
         let input = "f = (x : (y : x y))\ng = (z : z)\nf g t"
-        runTricu input @?= "Leaf"
+        tricuTestString input @?= "Leaf"
 
   , testCase "Lambda applied to string literal" $ do
         let input = "f = (x : x)\nf \"hello\""
-        runTricu input @?= "Fork (Fork Leaf (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) Leaf))))"
+        tricuTestString input @?= "Fork (Fork Leaf (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) Leaf))))"
 
 
    , testCase "Lambda applied to integer literal" $ do
         let input = "f = (x : x)\nf 42"
-        runTricu input @?= "Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) Leaf)))))"
+        tricuTestString input @?= "Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) Leaf)))))"
 
    , testCase "Lambda applied to list literal" $ do
         let input = "f = (x : x)\nf [t (t t)]"
-        runTricu input @?= "Fork Leaf (Fork (Stem Leaf) Leaf)"
+        tricuTestString input @?= "Fork Leaf (Fork (Stem Leaf) Leaf)"
 
   , testCase "Lambda containing list literal" $ do
       let input = "(a : [(a)]) 1"
-      runTricu input @?= "Fork (Fork (Stem Leaf) Leaf) Leaf"
+      tricuTestString input @?= "Fork (Fork (Stem Leaf) Leaf) Leaf"
   ]
 
 providedLibraries :: TestTree

tricu.cabal

@@ -1,7 +1,7 @@
 cabal-version: 1.12
 
 name:           tricu
-version:        0.18.1
+version:        0.19.0
 description:    A micro-language for exploring Tree Calculus
 author:         James Eversole
 maintainer:     james@eversole.co