src/Language/PureScript/Declarations.hs · rowtype-yoga/purescript-native

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rowtype-yoga/purescript-native/src/Language/PureScript/Declarations.hs

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1-----------------------------------------------------------------------------

2--

3-- Module : Language.PureScript.Declarations

4-- Copyright : (c) Phil Freeman 2013

5-- License : MIT

6--

7-- Maintainer : Phil Freeman <paf31@cantab.net>

8-- Stability : experimental

9-- Portability :

10--

11-- | Data types for modules and declarations

12--

13-----------------------------------------------------------------------------

15{-# LANGUAGE DeriveDataTypeable #-}

17module Language.PureScript.Declarations where

19import Language.PureScript.Types

20import Language.PureScript.Names

21import Language.PureScript.Kinds

22import Language.PureScript.TypeClassDictionaries

23import Language.PureScript.CodeGen.JS.AST

24import Language.PureScript.Environment

26import qualified Data.Data as D

27import Data.Generics (mkQ, everything)

29-- |

30-- A precedence level for an infix operator

31--

32type Precedence = Integer

34-- |

35-- Associativity for infix operators

36--

37data Associativity = Infixl | Infixr | Infix deriving (D.Data, D.Typeable)

39instance Show Associativity where

40 show Infixl = "infixl"

41 show Infixr = "infixr"

42 show Infix = "infix"

44-- |

45-- Source position information

46--

47data SourcePos = SourcePos

48 {

49 -- |

50 -- Line number

51 --

52 sourcePosLine :: Int

53 -- |

54 -- Column number

55 --

56 , sourcePosColumn :: Int

57 } deriving (D.Data, D.Typeable)

59instance Show SourcePos where

60 show sp = "line " ++ show (sourcePosLine sp) ++ ", column " ++ show (sourcePosColumn sp)

62-- |

63-- Fixity data for infix operators

64--

65data Fixity = Fixity Associativity Precedence deriving (Show, D.Data, D.Typeable)

67-- |

68-- A module declaration, consisting of a module name, a list of declarations, and a list of the

69-- declarations that are explicitly imported. If the export list is Nothing, everything is exported.

70--

71data Module = Module ModuleName [Declaration] (Maybe [DeclarationRef]) deriving (Show, D.Data, D.Typeable)

73-- |

74-- An item in a list of explicit imports or exports

75--

76data DeclarationRef

77 -- |

78 -- A type constructor with data constructors

79 --

80 = TypeRef ProperName (Maybe [ProperName])

81 -- |

82 -- A value

83 --

84 | ValueRef Ident

85 -- |

86 -- A type class

87 --

88 | TypeClassRef ProperName

89 -- |

90 -- A type class instance, created during typeclass desugaring (name, class name, instance types)

91 --

92 | TypeInstanceRef Ident

93 deriving (Show, Eq, D.Data, D.Typeable)

95-- |

96-- The data type of declarations

97--

98data Declaration

99 -- |

100 -- A data type declaration (name, arguments, data constructors)

101 --

102 = DataDeclaration ProperName [String] [(ProperName, [Type])]

103 -- |

104 -- A minimal mutually recursive set of data type declarations

105 --

106 | DataBindingGroupDeclaration [Declaration]

107 -- |

108 -- A type synonym declaration (name, arguments, type)

109 --

110 | TypeSynonymDeclaration ProperName [String] Type

111 -- |

112 -- A type declaration for a value (name, ty)

113 --

114 | TypeDeclaration Ident Type

115 -- |

116 -- A value declaration (name, top-level binders, optional guard, value)

117 --

118 | ValueDeclaration Ident NameKind [Binder] (Maybe Guard) Value

119 -- |

120 -- A minimal mutually recursive set of value declarations

121 --

122 | BindingGroupDeclaration [(Ident, NameKind, Value)]

123 -- |

124 -- A foreign import declaration (type, name, optional inline Javascript, type)

125 --

126 | ExternDeclaration ForeignImportType Ident (Maybe JS) Type

127 -- |

128 -- A data type foreign import (name, kind)

129 --

130 | ExternDataDeclaration ProperName Kind

131 -- |

132 -- A type class instance foreign import

133 --

134 | ExternInstanceDeclaration Ident [(Qualified ProperName, [Type])] (Qualified ProperName) [Type]

135 -- |

136 -- A fixity declaration (fixity data, operator name)

137 --

138 | FixityDeclaration Fixity String

139 -- |

140 -- A module import (module name, optional set of identifiers to import, optional "qualified as"

141 -- name)

142 --

143 | ImportDeclaration ModuleName (Maybe [DeclarationRef]) (Maybe ModuleName)

144 -- |

145 -- A type class declaration (name, argument, member declarations)

146 --

147 | TypeClassDeclaration ProperName [String] [Declaration]

148 -- |

149 -- A type instance declaration (name, dependencies, class name, instance types, member

150 -- declarations)

151 --

152 | TypeInstanceDeclaration Ident [(Qualified ProperName, [Type])] (Qualified ProperName) [Type] [Declaration]

153 -- |

154 -- A declaration with source position information

155 --

156 | PositionedDeclaration SourcePos Declaration

157 deriving (Show, D.Data, D.Typeable)

158

159-- |

160-- Test if a declaration is a value declaration

161--

162isValueDecl :: Declaration -> Bool

163isValueDecl ValueDeclaration{} = True

164isValueDecl (PositionedDeclaration _ d) = isValueDecl d

165isValueDecl _ = False

166

167-- |

168-- Test if a declaration is a data type or type synonym declaration

169--

170isDataDecl :: Declaration -> Bool

171isDataDecl DataDeclaration{} = True

172isDataDecl TypeSynonymDeclaration{} = True

173isDataDecl (PositionedDeclaration _ d) = isDataDecl d

174isDataDecl _ = False

175

176-- |

177-- Test if a declaration is a module import

178--

179isImportDecl :: Declaration -> Bool

180isImportDecl ImportDeclaration{} = True

181isImportDecl (PositionedDeclaration _ d) = isImportDecl d

182isImportDecl _ = False

183

184-- |

185-- Test if a declaration is a data type foreign import

186--

187isExternDataDecl :: Declaration -> Bool

188isExternDataDecl ExternDataDeclaration{} = True

189isExternDataDecl (PositionedDeclaration _ d) = isExternDataDecl d

190isExternDataDecl _ = False

191

192-- |

193-- Test if a declaration is a type class instance foreign import

194--

195isExternInstanceDecl :: Declaration -> Bool

196isExternInstanceDecl ExternInstanceDeclaration{} = True

197isExternInstanceDecl (PositionedDeclaration _ d) = isExternInstanceDecl d

198isExternInstanceDecl _ = False

199

200-- |

201-- Test if a declaration is a fixity declaration

202--

203isFixityDecl :: Declaration -> Bool

204isFixityDecl FixityDeclaration{} = True

205isFixityDecl (PositionedDeclaration _ d) = isFixityDecl d

206isFixityDecl _ = False

207

208-- |

209-- Test if a declaration is a foreign import

210--

211isExternDecl :: Declaration -> Bool

212isExternDecl ExternDeclaration{} = True

213isExternDecl (PositionedDeclaration _ d) = isExternDecl d

214isExternDecl _ = False

215

216-- |

217-- Test if a declaration is a type class or instance declaration

218--

219isTypeClassDeclaration :: Declaration -> Bool

220isTypeClassDeclaration TypeClassDeclaration{} = True

221isTypeClassDeclaration TypeInstanceDeclaration{} = True

222isTypeClassDeclaration (PositionedDeclaration _ d) = isTypeClassDeclaration d

223isTypeClassDeclaration _ = False

224

225-- |

226-- A guard is just a boolean-valued expression that appears alongside a set of binders

227--

228type Guard = Value

229

230-- |

231-- Data type for values

232--

233data Value

234 -- |

235 -- A numeric literal

236 --

237 = NumericLiteral (Either Integer Double)

238 -- |

239 -- A string literal

240 --

241 | StringLiteral String

242 -- |

243 -- A boolean literal

244 --

245 | BooleanLiteral Bool

246 -- |

247 -- A prefix -, will be desugared

248 --

249 | UnaryMinus Value

250 -- |

251 -- Binary operator application. During the rebracketing phase of desugaring, this data constructor

252 -- will be removed.

253 --

254 | BinaryNoParens (Qualified Ident) Value Value

255 -- |

256 -- Explicit parentheses. During the rebracketing phase of desugaring, this data constructor

257 -- will be removed.

258 --

259 | Parens Value

260 -- |

261 -- An array literal

262 --

263 | ArrayLiteral [Value]

264 -- |

265 -- An object literal

266 --

267 | ObjectLiteral [(String, Value)]

268 -- |

269 -- An record property accessor expression

270 --

271 | Accessor String Value

272 -- |

273 -- Partial record update

274 --

275 | ObjectUpdate Value [(String, Value)]

276 -- |

277 -- Function introduction

278 --

279 | Abs (Either Ident Binder) Value

280 -- |

281 -- Function application

282 --

283 | App Value Value

284 -- |

285 -- Variable

286 --

287 | Var (Qualified Ident)

288 -- |

289 -- Conditional (if-then-else expression)

290 --

291 | IfThenElse Value Value Value

292 -- |

293 -- A data constructor

294 --

295 | Constructor (Qualified ProperName)

296 -- |

297 -- A case expression. During the case expansion phase of desugaring, top-level binders will get

298 -- desugared into case expressions, hence the need for guards and multiple binders per branch here.

299 --

300 | Case [Value] [CaseAlternative]

301 -- |

302 -- A value with a type annotation

303 --

304 | TypedValue Bool Value Type

305 -- |

306 -- A let binding

307 --

308 | Let [Declaration] Value

309 -- |

310 -- A do-notation block

311 --

312 | Do [DoNotationElement]

313 -- |

314 -- A placeholder for a type class dictionary to be inserted later. At the end of type checking, these

315 -- placeholders will be replaced with actual expressions representing type classes dictionaries which

316 -- can be evaluated at runtime. The constructor arguments represent (in order): the type class name and

317 -- instance type, and the type class dictionaries in scope.

318 --

319 | TypeClassDictionary (Qualified ProperName, [Type]) [TypeClassDictionaryInScope]

320 -- |

321 -- A value with source position information

322 --

323 | PositionedValue SourcePos Value deriving (Show, D.Data, D.Typeable)

324

325-- |

326-- An alternative in a case statement

327--

328data CaseAlternative = CaseAlternative

329 { -- |

330 -- A collection of binders with which to match the inputs

331 --

332 caseAlternativeBinders :: [Binder]

333 -- |

334 -- An optional guard

335 --

336 , caseAlternativeGuard :: Maybe Guard

337 -- |

338 -- The result expression

339 --

340 , caseAlternativeResult :: Value

341 } deriving (Show, D.Data, D.Typeable)

342

343-- |

344-- Find the original dictionary which a type class dictionary in scope refers to

345--

346canonicalizeDictionary :: TypeClassDictionaryInScope -> Qualified Ident

347canonicalizeDictionary (TypeClassDictionaryInScope { tcdType = TCDRegular, tcdName = nm }) = nm

348canonicalizeDictionary (TypeClassDictionaryInScope { tcdType = TCDAlias nm }) = nm

349

350-- |

351-- A statement in a do-notation block

352--

353data DoNotationElement

354 -- |

355 -- A monadic value without a binder

356 --

357 = DoNotationValue Value

358 -- |

359 -- A monadic value with a binder

360 --

361 | DoNotationBind Binder Value

362 -- |

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

364 --

365 | DoNotationLet Binder Value

366 -- |

367 -- A do notation element with source position information

368 --

369 | PositionedDoNotationElement SourcePos DoNotationElement deriving (Show, D.Data, D.Typeable)

370

371-- |

372-- Data type for binders

373--

374data Binder

375 -- |

376 -- Wildcard binder

377 --

378 = NullBinder

379 -- |

380 -- A binder which matches a boolean literal

381 --

382 | BooleanBinder Bool

383 -- |

384 -- A binder which matches a string literal

385 --

386 | StringBinder String

387 -- |

388 -- A binder which matches a numeric literal

389 --

390 | NumberBinder (Either Integer Double)

391 -- |

392 -- A binder which binds an identifier

393 --

394 | VarBinder Ident

395 -- |

396 -- A binder which matches a data constructor

397 --

398 | ConstructorBinder (Qualified ProperName) [Binder]

399 -- |

400 -- A binder which matches a record and binds its properties

401 --

402 | ObjectBinder [(String, Binder)]

403 -- |

404 -- A binder which matches an array and binds its elements

405 --

406 | ArrayBinder [Binder]

407 -- |

408 -- A binder which matches an array and binds its head and tail

409 --

410 | ConsBinder Binder Binder

411 -- |

412 -- A binder which binds its input to an identifier

413 --

414 | NamedBinder Ident Binder

415 -- |

416 -- A binder with source position information

417 --

418 | PositionedBinder SourcePos Binder deriving (Show, D.Data, D.Typeable)

419

420-- |

421-- Collect all names introduced in binders in an expression

422--

423binderNames :: (D.Data d) => d -> [Ident]

424binderNames = everything (++) (mkQ [] go)

425 where

426 go (VarBinder ident) = [ident]

427 go (NamedBinder ident _) = [ident]

428 go _ = []