abd72b6 · rowtype-yoga/purescript-native

git.iko.soy/rowtype-yoga/purescript-native

Fix a bug involving let bindings and unused variable removal. Support extended let in do-notation.

commitabd72b6a877829aa6c68a185b4e8768919c78ad8 authorPhil Freeman <paf31@cantab.net> dateWed 2 Apr 2014, 18:01 (13 years ago) parent649628d

8 files changed+32−19

compare with golang

unifiedsplit

examples/passing/Do.purs+10−2 examples/passing/Let.purs+7−1 purescript.cabal+1−1 src/Language/PureScript/Declarations.hs+1−1 src/Language/PureScript/Optimizer/Unused.hs+7−5 src/Language/PureScript/Parser/Declarations.hs+1−2 src/Language/PureScript/Pretty/Values.hs+2−4 src/Language/PureScript/Sugar/DoNotation.hs+3−3

examples/passing/Do.purs+10−2

@@ -35,8 +35,10 @@ test5 mx my mz = do

3535 Just (z + sum + 1)

3636

3737test6 mx = \_ -> do

38− let Just x = mx

39− Just x

38+ let

39+ f :: forall a. Maybe a -> a

40+ f (Just x) = x

41+ Just (f mx)

4042

4143test8 = \_ -> do

4244 Just (do

@@ -44,4 +46,10 @@ test8 = \_ -> do

4446

4547test9 = \_ -> (+) <$> Just 1 <*> Just 2

4648

49+test10 _ = do

50+ let

51+ f x = g x * 3

52+ g x = f x / 2

53+ Just (f 10)

54+

4755main = Debug.Trace.trace "Done"

examples/passing/Let.purs+7−1

@@ -24,7 +24,7 @@ test5 = let

2424 f x | x > 0 = g (x / 2) + 1

2525 f x = 0

2626 g x = f (x - 1) + 1

27− in g 10

27+ in f 10

2828

2929test6 = runPure (runST (do

3030 r <- newSTRef 0

@@ -47,6 +47,12 @@ test8 x = let

4747 go y = go $ (y + x / y) / 2

4848 in go x

4949

50+test10 _ =

51+ let

52+ f x = g x * 3

53+ g x = f x / 2

54+ in f 10

55+

5056main = do

5157 Debug.Trace.print (test1 1)

5258 Debug.Trace.print (test2 1 2)

purescript.cabal+1−1

@@ -1,5 +1,5 @@

11name: purescript

2−version: 0.4.12.1

2+version: 0.4.13

33cabal-version: >=1.8

44build-type: Custom

55license: MIT

src/Language/PureScript/Declarations.hs+1−1

@@ -378,7 +378,7 @@ data DoNotationElement

378378 -- |

379379 -- A let statement, i.e. a pure value with a binder

380380 --

381− | DoNotationLet Binder Value

381+ | DoNotationLet [Declaration]

382382 -- |

383383 -- A do notation element with source position information

384384 --

src/Language/PureScript/Optimizer/Unused.hs+7−5

@@ -24,12 +24,14 @@ import Language.PureScript.CodeGen.JS.AST

2424import Language.PureScript.Optimizer.Common

2525

2626removeUnusedVariables :: JS -> JS

27−removeUnusedVariables = everywhere (mkT $ removeFromBlock go)

27+removeUnusedVariables = everywhere (mkT $ removeFromBlock withBlock)

2828 where

29− go :: [JS] -> [JS]

30− go [] = []

31− go (JSVariableIntroduction var _ : sts) | not (isUsed var sts) = go sts

32− go (s:sts) = s : go sts

29+ withBlock :: [JS] -> [JS]

30+ withBlock sts = go sts sts

31+ go :: [JS] -> [JS] -> [JS]

32+ go _ [] = []

33+ go sts (JSVariableIntroduction var _ : rest) | not (isUsed var sts) = go sts rest

34+ go sts (s : rest) = s : go sts rest

3335

3436removeCodeAfterReturnStatements :: JS -> JS

3537removeCodeAfterReturnStatements = everywhere (mkT $ removeFromBlock go)

src/Language/PureScript/Parser/Declarations.hs+1−2

@@ -306,8 +306,7 @@ parseDo = do

306306 Do <$> C.mark (P.many (C.same *> C.mark parseDoNotationElement))

307307

308308parseDoNotationLet :: P.Parsec String ParseState DoNotationElement

309−parseDoNotationLet = DoNotationLet <$> (C.reserved "let" *> C.indented *> parseBinder)

310− <*> (C.indented *> C.reservedOp "=" *> parseValue)

309+parseDoNotationLet = DoNotationLet <$> (C.reserved "let" *> C.indented *> C.mark (P.many1 (C.same *> parseLocalDeclaration)))

311310

312311parseDoNotationBind :: P.Parsec String ParseState DoNotationElement

313312parseDoNotationBind = DoNotationBind <$> parseBinder <*> (C.indented *> C.reservedOp "<-" *> parseValue)

src/Language/PureScript/Pretty/Values.hs+2−4

@@ -104,12 +104,10 @@ prettyPrintDoNotationElement (DoNotationBind binder val) =

104104 , return " <- "

105105 , prettyPrintValue' val

106106 ]

107−prettyPrintDoNotationElement (DoNotationLet binder val) =

107+prettyPrintDoNotationElement (DoNotationLet ds) =

108108 fmap concat $ sequence

109109 [ return "let "

110− , prettyPrintBinder' binder

111− , return " = "

112− , prettyPrintValue' val

110+ , withIndent $ prettyPrintMany prettyPrintDeclaration ds

113111 ]

114112prettyPrintDoNotationElement (PositionedDoNotationElement _ el) = prettyPrintDoNotationElement el

115113

src/Language/PureScript/Sugar/DoNotation.hs+3−3

@@ -59,8 +59,8 @@ desugarDo = everywhereM (mkM replace)

5959 rest' <- go rest

6060 let ident = head $ unusedNames rest'

6161 return $ App (App bind val) (Abs (Left ident) (Case [Var (Qualified Nothing ident)] [CaseAlternative [binder] Nothing rest']))

62− go [DoNotationLet _ _] = Left $ mkErrorStack "Let statement cannot be the last statement in a do block" Nothing

63− go (DoNotationLet binder val : rest) = do

62+ go [DoNotationLet _] = Left $ mkErrorStack "Let statement cannot be the last statement in a do block" Nothing

63+ go (DoNotationLet ds : rest) = do

6464 rest' <- go rest

65− return $ Case [val] [CaseAlternative [binder] Nothing rest']

65+ return $ Let ds rest'

6666 go (PositionedDoNotationElement pos el : rest) = PositionedValue pos <$> go (el : rest)