ec3e3f1 · rowtype-yoga/purescript-native

examples/passing/ObjectUpdater.pursnew file+23

compare with golang

unifiedsplit

@@ -0,0 +1,23 @@

1+module Main where

2+

3+import Control.Monad.Eff

4+import Debug.Trace

5+

6+foreign import data Error :: !

7+

8+foreign import error

9+ """

10+ function error() {

11+ throw new Error("Object update failed");

12+ }

13+ """ :: forall e. Eff (error :: Error | e) Unit

14+

15+getValue :: forall e. Eff (| e) Boolean

16+getValue = return true

17+

18+main = do

19+ let record = { value: false }

20+ record2 <- record { value = _ } <$> getValue

21+ if record2.value

22+ then trace "Done"

23+ else error

src/Language/PureScript/AST/Declarations.hs+5

@@ -338,6 +338,11 @@ data Expr

338 --

339 | ObjectUpdate Expr [(String, Expr)]

340 -- |

341+ -- Partial record updater. This will be removed during desugaring and

342+ -- expanded into a lambda that returns an object update.

343+ --

344+ | ObjectUpdater Expr [(String, Maybe Expr)]

345+ -- |

341 -- Function introduction

346 -- Function introduction

342 --

347 --

343 | Abs (Either Ident Binder) Expr

348 | Abs (Either Ident Binder) Expr

src/Language/PureScript/Parser/Declarations.hs+4−4

@@ -345,7 +345,7 @@ parseValueAtom = P.choice

345 , P.try parseBooleanLiteral

346 , parseArrayLiteral

347 , P.try parseObjectLiteral

348− , parseObjectGetter

348+ , P.try parseObjectGetter

349 , parseAbs

350 , P.try parseConstructor

351 , P.try parseVar

@@ -355,11 +355,11 @@ parseValueAtom = P.choice

355 , parseLet

356 , Parens <$> parens parseValue ]

357

358−parsePropertyUpdate :: TokenParser (String, Expr)

358+parsePropertyUpdate :: TokenParser (String, Maybe Expr)

359parsePropertyUpdate = do

360 name <- lname <|> stringLiteral

361 _ <- C.indented *> equals

362− value <- C.indented *> parseValue

362+ value <- C.indented *> (underscore *> pure Nothing) <|> (Just <$> parseValue)

363 return (name, value)

364

365parseAccessor :: Expr -> TokenParser Expr

@@ -398,7 +398,7 @@ parseValue = withSourceSpan PositionedValue

398 where

399 indexersAndAccessors = C.buildPostfixParser postfixTable1 parseValueAtom

400 postfixTable1 = [ parseAccessor

401− , \v -> P.try $ flip ObjectUpdate <$> (C.indented *> braces (commaSep1 (C.indented *> parsePropertyUpdate))) <*> pure v ]

401+ , \v -> P.try $ flip ObjectUpdater <$> (C.indented *> braces (commaSep1 (C.indented *> parsePropertyUpdate))) <*> pure v ]

402 postfixTable2 = [ \v -> P.try (flip App <$> (C.indented *> indexersAndAccessors)) <*> pure v

403 , \v -> flip (TypedValue True) <$> (P.try (C.indented *> doubleColon) *> parsePolyType) <*> pure v

404 ]

src/Language/PureScript/Sugar/ObjectWildcards.hs+9−5

@@ -32,15 +32,19 @@ desugarObjectConstructors (Module mn ds exts) = Module mn (map desugarDecl ds) e

32 (desugarDecl, _, _) = everywhereOnValues id desugarExpr id

33

34 desugarExpr :: Expr -> Expr

35− desugarExpr (ObjectConstructor ps) =

35+ desugarExpr (ObjectConstructor ps) = wrapLambda ObjectLiteral ps

36− let (props, args) = partition (isJust . snd) ps

36+ desugarExpr (ObjectUpdater obj ps) = wrapLambda (ObjectUpdate obj) ps

37− in if null args

38− then ObjectLiteral $ second fromJust `map` props

39− else foldr (Abs . Left . Ident . fst) (ObjectLiteral (mkProp `map` ps)) args

40 desugarExpr (ObjectGetter prop) =

37 desugarExpr (ObjectGetter prop) =

41 Abs (Left (Ident "obj")) (Accessor prop (Var (Qualified Nothing (Ident "obj"))))

38 Abs (Left (Ident "obj")) (Accessor prop (Var (Qualified Nothing (Ident "obj"))))

42 desugarExpr e = e

39 desugarExpr e = e

43

40

41+ wrapLambda :: ([(String, Expr)] -> Expr) -> [(String, Maybe Expr)] -> Expr

42+ wrapLambda mkVal ps =

43+ let (props, args) = partition (isJust . snd) ps

44+ in if null args

45+ then mkVal $ second fromJust `map` props

46+ else foldr (Abs . Left . Ident . fst) (mkVal (mkProp `map` ps)) args

47+

44 mkProp :: (String, Maybe Expr) -> (String, Expr)

48 mkProp :: (String, Maybe Expr) -> (String, Expr)

45 mkProp (name, Just e) = (name, e)

49 mkProp (name, Just e) = (name, e)

46 mkProp (name, Nothing) = (name, Var (Qualified Nothing (Ident name)))

50 mkProp (name, Nothing) = (name, Var (Qualified Nothing (Ident name)))