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 -- Source name

50 --

51 sourceName :: String

52 -- |

53 -- Line number

54 --

55 , sourcePosLine :: Int

56 -- |

57 -- Column number

58 --

59 , sourcePosColumn :: Int

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

62instance Show SourcePos where

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

65-- |

66-- Fixity data for infix operators

67--

68data Fixity = Fixity Associativity Precedence deriving (Show, D.Data, D.Typeable)

70-- |

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

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

73--

74data Module = Module ModuleName [Declaration] (Maybe [DeclarationRef]) deriving (Show, D.Data, D.Typeable)

76-- |

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

78--

79data DeclarationRef

80 -- |

81 -- A type constructor with data constructors

82 --

83 = TypeRef ProperName (Maybe [ProperName])

84 -- |

85 -- A value

86 --

87 | ValueRef Ident

88 -- |

89 -- A type class

90 --

91 | TypeClassRef ProperName

92 -- |

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

94 --

95 | TypeInstanceRef Ident

96 -- |

97 -- A declaration reference with source position information

98 --

99 | PositionedDeclarationRef SourcePos DeclarationRef

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

101

102instance Eq DeclarationRef where

103 (TypeRef name dctors) == (TypeRef name' dctors') = name == name' && dctors == dctors'

104 (ValueRef name) == (ValueRef name') = name == name'

105 (TypeClassRef name) == (TypeClassRef name') = name == name'

106 (TypeInstanceRef name) == (TypeInstanceRef name') = name == name'

107 (PositionedDeclarationRef _ r) == r' = r == r'

108 r == (PositionedDeclarationRef _ r') = r == r'

109 _ == _ = False

110

111-- |

112-- The data type of declarations

113--

114data Declaration

115 -- |

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

117 --

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

119 -- |

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

121 --

122 | DataBindingGroupDeclaration [Declaration]

123 -- |

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

125 --

126 | TypeSynonymDeclaration ProperName [String] Type

127 -- |

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

129 --

130 | TypeDeclaration Ident Type

131 -- |

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

133 --

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

135 -- |

136 -- A minimal mutually recursive set of value declarations

137 --

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

139 -- |

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

141 --

142 | ExternDeclaration ForeignImportType Ident (Maybe JS) Type

143 -- |

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

145 --

146 | ExternDataDeclaration ProperName Kind

147 -- |

148 -- A type class instance foreign import

149 --

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

151 -- |

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

153 --

154 | FixityDeclaration Fixity String

155 -- |

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

157 -- name)

158 --

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

160 -- |

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

162 --

163 | TypeClassDeclaration ProperName [String] [Declaration]

164 -- |

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

166 -- declarations)

167 --

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

169 -- |

170 -- A declaration with source position information

171 --

172 | PositionedDeclaration SourcePos Declaration

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

174

175-- |

176-- Test if a declaration is a value declaration

177--

178isValueDecl :: Declaration -> Bool

179isValueDecl ValueDeclaration{} = True

180isValueDecl (PositionedDeclaration _ d) = isValueDecl d

181isValueDecl _ = False

182

183-- |

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

185--

186isDataDecl :: Declaration -> Bool

187isDataDecl DataDeclaration{} = True

188isDataDecl TypeSynonymDeclaration{} = True

189isDataDecl (PositionedDeclaration _ d) = isDataDecl d

190isDataDecl _ = False

191

192-- |

193-- Test if a declaration is a module import

194--

195isImportDecl :: Declaration -> Bool

196isImportDecl ImportDeclaration{} = True

197isImportDecl (PositionedDeclaration _ d) = isImportDecl d

198isImportDecl _ = False

199

200-- |

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

202--

203isExternDataDecl :: Declaration -> Bool

204isExternDataDecl ExternDataDeclaration{} = True

205isExternDataDecl (PositionedDeclaration _ d) = isExternDataDecl d

206isExternDataDecl _ = False

207

208-- |

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

210--

211isExternInstanceDecl :: Declaration -> Bool

212isExternInstanceDecl ExternInstanceDeclaration{} = True

213isExternInstanceDecl (PositionedDeclaration _ d) = isExternInstanceDecl d

214isExternInstanceDecl _ = False

215

216-- |

217-- Test if a declaration is a fixity declaration

218--

219isFixityDecl :: Declaration -> Bool

220isFixityDecl FixityDeclaration{} = True

221isFixityDecl (PositionedDeclaration _ d) = isFixityDecl d

222isFixityDecl _ = False

223

224-- |

225-- Test if a declaration is a foreign import

226--

227isExternDecl :: Declaration -> Bool

228isExternDecl ExternDeclaration{} = True

229isExternDecl (PositionedDeclaration _ d) = isExternDecl d

230isExternDecl _ = False

231

232-- |

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

234--

235isTypeClassDeclaration :: Declaration -> Bool

236isTypeClassDeclaration TypeClassDeclaration{} = True

237isTypeClassDeclaration TypeInstanceDeclaration{} = True

238isTypeClassDeclaration (PositionedDeclaration _ d) = isTypeClassDeclaration d

239isTypeClassDeclaration _ = False

240

241-- |

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

243--

244type Guard = Value

245

246-- |

247-- Data type for values

248--

249data Value

250 -- |

251 -- A numeric literal

252 --

253 = NumericLiteral (Either Integer Double)

254 -- |

255 -- A string literal

256 --

257 | StringLiteral String

258 -- |

259 -- A boolean literal

260 --

261 | BooleanLiteral Bool

262 -- |

263 -- A prefix -, will be desugared

264 --

265 | UnaryMinus Value

266 -- |

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

268 -- will be removed.

269 --

270 | BinaryNoParens (Qualified Ident) Value Value

271 -- |

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

273 -- will be removed.

274 --

275 | Parens Value

276 -- |

277 -- An array literal

278 --

279 | ArrayLiteral [Value]

280 -- |

281 -- An object literal

282 --

283 | ObjectLiteral [(String, Value)]

284 -- |

285 -- An record property accessor expression

286 --

287 | Accessor String Value

288 -- |

289 -- Partial record update

290 --

291 | ObjectUpdate Value [(String, Value)]

292 -- |

293 -- Function introduction

294 --

295 | Abs (Either Ident Binder) Value

296 -- |

297 -- Function application

298 --

299 | App Value Value

300 -- |

301 -- Variable

302 --

303 | Var (Qualified Ident)

304 -- |

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

306 --

307 | IfThenElse Value Value Value

308 -- |

309 -- A data constructor

310 --

311 | Constructor (Qualified ProperName)

312 -- |

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

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

315 --

316 | Case [Value] [CaseAlternative]

317 -- |

318 -- A value with a type annotation

319 --

320 | TypedValue Bool Value Type

321 -- |

322 -- A let binding

323 --

324 | Let [Declaration] Value

325 -- |

326 -- A do-notation block

327 --

328 | Do [DoNotationElement]

329 -- |

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

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

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

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

334 --

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

336 -- |

337 -- A value with source position information

338 --

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

340

341-- |

342-- An alternative in a case statement

343--

344data CaseAlternative = CaseAlternative

345 { -- |

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

347 --

348 caseAlternativeBinders :: [Binder]

349 -- |

350 -- An optional guard

351 --

352 , caseAlternativeGuard :: Maybe Guard

353 -- |

354 -- The result expression

355 --

356 , caseAlternativeResult :: Value

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

358

359-- |

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

361--

362canonicalizeDictionary :: TypeClassDictionaryInScope -> Qualified Ident

363canonicalizeDictionary (TypeClassDictionaryInScope { tcdType = TCDRegular, tcdName = nm }) = nm

364canonicalizeDictionary (TypeClassDictionaryInScope { tcdType = TCDAlias nm }) = nm

365

366-- |

367-- A statement in a do-notation block

368--

369data DoNotationElement

370 -- |

371 -- A monadic value without a binder

372 --

373 = DoNotationValue Value

374 -- |

375 -- A monadic value with a binder

376 --

377 | DoNotationBind Binder Value

378 -- |

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

380 --

381 | DoNotationLet [Declaration]

382 -- |

383 -- A do notation element with source position information

384 --

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

386

387-- |

388-- Data type for binders

389--

390data Binder

391 -- |

392 -- Wildcard binder

393 --

394 = NullBinder

395 -- |

396 -- A binder which matches a boolean literal

397 --

398 | BooleanBinder Bool

399 -- |

400 -- A binder which matches a string literal

401 --

402 | StringBinder String

403 -- |

404 -- A binder which matches a numeric literal

405 --

406 | NumberBinder (Either Integer Double)

407 -- |

408 -- A binder which binds an identifier

409 --

410 | VarBinder Ident

411 -- |

412 -- A binder which matches a data constructor

413 --

414 | ConstructorBinder (Qualified ProperName) [Binder]

415 -- |

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

417 --

418 | ObjectBinder [(String, Binder)]

419 -- |

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

421 --

422 | ArrayBinder [Binder]

423 -- |

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

425 --

426 | ConsBinder Binder Binder

427 -- |

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

429 --

430 | NamedBinder Ident Binder

431 -- |

432 -- A binder with source position information

433 --

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

435

436-- |

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

438--

439binderNames :: (D.Data d) => d -> [Ident]

440binderNames = everything (++) (mkQ [] go)

441 where

442 go (VarBinder ident) = [ident]

443 go (NamedBinder ident _) = [ident]

444 go _ = []