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| 1 | namespace Syntax.Parsers.Expressions is | |
| 2 | use IO.Std; | |
| 3 | ||
| 4 | use Source; | |
| 5 | ||
| 6 | use Logging; | |
| 7 | ||
| 8 | class PRIMARY( | |
| 9 | identifier_parser: Parser[Trees.Identifiers.Identifier], | |
| 10 | type_parser: Parser[Trees.TypeExpressions.TypeExpression], | |
| 11 | expression_parser: Parser[Trees.Expressions.Expression], | |
| 12 | expression_list_parser: Parser[Trees.Expressions.LIST], | |
| 13 | expression_tuple_parser: Parser[Trees.Expressions.TUPLE], | |
| 14 | statement_parser: Parser[Trees.Statements.Statement], | |
| 15 | statement_list_parser: Parser[Trees.Statements.LIST], | |
| 16 | variable_list_parser: Parser[Trees.Variables.LIST], | |
| 17 | pragma_parser: Parser[Trees.Pragmas.PRAGMA] | |
| 18 | ): Base[Trees.Expressions.Expression] is | |
| 19 | description: string => "primary expression"; | |
| 20 | ||
| 21 | super(); | |
| 22 | ||
| 23 | init(..) is | |
| 24 | add_parsers(); | |
| 25 | si | |
| 26 | ||
| 27 | // `@Foo() name: T` — an attribute pragma on a lambda-literal | |
| 28 | // parameter. Recognised only where a tuple element (and so | |
| 29 | // potentially a lambda parameter) can start — everywhere else | |
| 30 | // `@` falls through to the base dispatch and its ordinary | |
| 31 | // "unexpected token" error, so it never shows up as a spurious | |
| 32 | // option in an unrelated "expected ..." diagnostic. Whether | |
| 33 | // this position genuinely turns out to be a lambda parameter | |
| 34 | // (as opposed to an element of a value tuple that was never | |
| 35 | // rewritten into one) is checked once the enclosing construct | |
| 36 | // is known — see COMPILE_TUPLES.visit_tuple and | |
| 37 | // TUPLE_ELEMENT.rewrite_as_expression. | |
| 38 | parse(context: CONTEXT) -> Trees.Expressions.Expression? is | |
| 39 | if context.current.token == Lexical.TOKEN.AT /\ context.allow_tuple_element then | |
| 40 | return _parse_pragma_variable(context); | |
| 41 | fi | |
| 42 | ||
| 43 | return super.parse(context); | |
| 44 | si | |
| 45 | ||
| 46 | _parse_pragma_variable(context: CONTEXT) -> Trees.Expressions.Expression is | |
| 47 | let start = context.location; | |
| 48 | ||
| 49 | let pragmas = Collections.LIST[Trees.Pragmas.PRAGMA](); | |
| 50 | ||
| 51 | while context.current.token == Lexical.TOKEN.AT do | |
| 52 | let pragma = pragma_parser.parse(context); | |
| 53 | ||
| 54 | if !pragma? then | |
| 55 | break; | |
| 56 | fi | |
| 57 | ||
| 58 | pragmas.add(pragma); | |
| 59 | od | |
| 60 | ||
| 61 | context.allow_tuple_element = false; | |
| 62 | ||
| 63 | let identifier = identifier_parser.parse(context)!; | |
| 64 | ||
| 65 | if identifier.is_qualified then | |
| 66 | context.error(identifier.location, "expected a simple parameter name here"); | |
| 67 | fi | |
| 68 | ||
| 69 | let end mut = identifier.location; | |
| 70 | let type_expression: Trees.TypeExpressions.TypeExpression mut = Trees.TypeExpressions.INFER(identifier.location); | |
| 71 | let initializer: Trees.Expressions.Expression? mut = null; | |
| 72 | ||
| 73 | if context.current.token == Lexical.TOKEN.COLON then | |
| 74 | context.next_token(); | |
| 75 | let parsed_type = type_parser.parse(context); | |
| 76 | ||
| 77 | if parsed_type? then | |
| 78 | type_expression = parsed_type; | |
| 79 | end = parsed_type.location; | |
| 80 | fi | |
| 81 | fi | |
| 82 | ||
| 83 | if context.current.token == Lexical.TOKEN.ASSIGN then | |
| 84 | context.next_token(); | |
| 85 | initializer = expression_parser.parse(context); | |
| 86 | ||
| 87 | if initializer? then | |
| 88 | end = initializer.location; | |
| 89 | fi | |
| 90 | fi | |
| 91 | ||
| 92 | let result = Trees.Expressions.VARIABLE(start::end, identifier, type_expression, initializer); | |
| 93 | result.set_pragmas(pragmas); | |
| 94 | ||
| 95 | return result; | |
| 96 | si | |
| 97 | ||
| 98 | add_parsers() is | |
| 99 | add_parser( | |
| 100 | (context) -> Trees.Expressions.Expression is | |
| 101 | let start = context.location; | |
| 102 | let identifier = identifier_parser.parse(context)!; | |
| 103 | ||
| 104 | // A bare unqualified `_` in a value position is the | |
| 105 | // default-value expression. The `: T` and `= init` | |
| 106 | // guards keep the typed-discard formal `_: T` on the | |
| 107 | // identifier path. Binding and pattern positions | |
| 108 | // (`let _ =`, destructure leaves, `for _`, `if let`) | |
| 109 | // never reach this parser — they parse identifiers | |
| 110 | // directly — so the discard meanings don't collide | |
| 111 | // with the value meaning. Inside a `(...)` group the | |
| 112 | // speculative tuple/pattern rewrite converts a `_` | |
| 113 | // element back to a discard leaf via DEFAULT's | |
| 114 | // try_copy_as_*. | |
| 115 | if | |
| 116 | identifier.name =~ "_" /\ | |
| 117 | !identifier.is_qualified /\ | |
| 118 | context.current.token != Lexical.TOKEN.COLON /\ | |
| 119 | context.current.token != Lexical.TOKEN.ASSIGN | |
| 120 | then | |
| 121 | // `_[T]` pins the type explicitly. `_` is | |
| 122 | // never indexable, so a `[` here is the type | |
| 123 | // argument, not an indexer. | |
| 124 | let type_expression: Trees.TypeExpressions.TypeExpression? mut = null; | |
| 125 | ||
| 126 | if context.current_token == Lexical.TOKEN.SQUARE_OPEN then | |
| 127 | context.next_token(); | |
| 128 | type_expression = type_parser.parse(context); | |
| 129 | context.next_token(Lexical.TOKEN.SQUARE_CLOSE); | |
| 130 | fi | |
| 131 | ||
| 132 | return Trees.Expressions.DEFAULT(start::context.location, type_expression); | |
| 133 | fi | |
| 134 | ||
| 135 | if context.allow_tuple_element /\ !identifier.is_qualified then | |
| 136 | context.allow_tuple_element = false; | |
| 137 | let end mut = identifier.location; | |
| 138 | let type_expression: Trees.TypeExpressions.TypeExpression? mut = null; | |
| 139 | let initializer: Trees.Expressions.Expression? mut = null; | |
| 140 | ||
| 141 | if context.current.token == Lexical.TOKEN.COLON then | |
| 142 | context.next_token(); | |
| 143 | type_expression = type_parser.parse(context); | |
| 144 | end = type_expression!.location; | |
| 145 | fi | |
| 146 | ||
| 147 | if context.current.token == Lexical.TOKEN.ASSIGN then | |
| 148 | context.next_token(); | |
| 149 | initializer = expression_parser.parse(context); | |
| 150 | end = initializer!.location; | |
| 151 | fi | |
| 152 | ||
| 153 | if initializer? then | |
| 154 | if type_expression == null then | |
| 155 | type_expression = Trees.TypeExpressions.INFER(context.location); | |
| 156 | fi | |
| 157 | fi | |
| 158 | ||
| 159 | if type_expression? then | |
| 160 | return Trees.Expressions.VARIABLE(start::end, identifier, type_expression, initializer); | |
| 161 | fi | |
| 162 | fi | |
| 163 | ||
| 164 | return Trees.Expressions.IDENTIFIER(identifier.location, identifier); | |
| 165 | si, Lexical.TOKEN.IDENTIFIER | |
| 166 | ); | |
| 167 | ||
| 168 | add_parser( | |
| 169 | (context) is | |
| 170 | let start = context.location; | |
| 171 | context.next_token(); | |
| 172 | ||
| 173 | // `[ ]` with the brackets tokenized separately is the | |
| 174 | // empty list literal, the same as the `[]` single token; | |
| 175 | // its element type comes from the surrounding context. | |
| 176 | let elements = | |
| 177 | if context.current.token == Lexical.TOKEN.SQUARE_CLOSE then | |
| 178 | Trees.Expressions.LIST(context.location, Collections.LIST[Trees.Expressions.Expression]()) | |
| 179 | else | |
| 180 | expression_list_parser.parse(context)! | |
| 181 | fi; | |
| 182 | ||
| 183 | let end mut = context.location; | |
| 184 | context.next_token(Lexical.TOKEN.SQUARE_CLOSE); | |
| 185 | let type_expression: Trees.TypeExpressions.TypeExpression = | |
| 186 | if context.current.token == Lexical.TOKEN.COLON then | |
| 187 | context.next_token(); | |
| 188 | let parsed = type_parser.parse(context)!; | |
| 189 | end = parsed.location; | |
| 190 | parsed | |
| 191 | else | |
| 192 | Trees.TypeExpressions.INFER(start::end) | |
| 193 | fi; | |
| 194 | ||
| 195 | return Trees.Expressions.SEQUENCE(start::end, elements, type_expression); | |
| 196 | si, | |
| 197 | Lexical.TOKEN.SQUARE_OPEN | |
| 198 | ); | |
| 199 | ||
| 200 | add_parser( | |
| 201 | (context) is | |
| 202 | // `[]` is a single token. As a value it is the empty | |
| 203 | // list literal: the element type can't come from the | |
| 204 | // (absent) elements, so it relies on a constraint pushed | |
| 205 | // down by the surrounding context — a typed initializer, | |
| 206 | // a call argument with a known formal type, and so on. | |
| 207 | // With no such constraint compile_tuples reports | |
| 208 | // "cannot infer type of list literal with no elements". | |
| 209 | let location = context.location; | |
| 210 | ||
| 211 | context.next_token(); | |
| 212 | ||
| 213 | return Trees.Expressions.SEQUENCE( | |
| 214 | location, | |
| 215 | Trees.Expressions.LIST(location, Collections.LIST[Trees.Expressions.Expression]()), | |
| 216 | Trees.TypeExpressions.INFER(location) | |
| 217 | ); | |
| 218 | si, | |
| 219 | Lexical.TOKEN.ARRAY_DEF | |
| 220 | ); | |
| 221 | ||
| 222 | add_parser( | |
| 223 | (context) is | |
| 224 | return expression_tuple_parser.parse(context)!; | |
| 225 | si, | |
| 226 | Lexical.TOKEN.PAREN_OPEN | |
| 227 | ); | |
| 228 | ||
| 229 | add_parser( | |
| 230 | (context) is | |
| 231 | let start = context.location; | |
| 232 | ||
| 233 | context.next_token(Lexical.TOKEN.NEW); | |
| 234 | ||
| 235 | // `new(args)` form: no explicit type, the type | |
| 236 | // is taken from the surrounding constraint | |
| 237 | // (LHS of an assignment / typed initializer / | |
| 238 | // call argument with a known formal type). | |
| 239 | // Distinguished from `new TYPE(args)` by an | |
| 240 | // immediately-following `(`. | |
| 241 | let type_expression: Trees.TypeExpressions.TypeExpression? mut = null; | |
| 242 | ||
| 243 | if context.current.token != Lexical.TOKEN.PAREN_OPEN then | |
| 244 | type_expression = type_parser.parse(context); | |
| 245 | fi | |
| 246 | ||
| 247 | let arguments: Trees.Expressions.LIST? mut = null; | |
| 248 | ||
| 249 | if context.next_token(Lexical.TOKEN.PAREN_OPEN) then | |
| 250 | if context.current.token != Lexical.TOKEN.PAREN_CLOSE then | |
| 251 | arguments = expression_list_parser.parse(context); | |
| 252 | fi | |
| 253 | context.next_token(Lexical.TOKEN.PAREN_CLOSE, syntax_error_message); | |
| 254 | fi | |
| 255 | ||
| 256 | if !arguments? then | |
| 257 | arguments = Trees.Expressions.LIST(context.location, Collections.LIST[Trees.Expressions.Expression]()); | |
| 258 | fi | |
| 259 | ||
| 260 | return Trees.Expressions.NEW(start::arguments.location, type_expression, arguments); | |
| 261 | si, | |
| 262 | Lexical.TOKEN.NEW | |
| 263 | ); | |
| 264 | ||
| 265 | add_parser( | |
| 266 | (context) is | |
| 267 | let start = context.location; | |
| 268 | ||
| 269 | context.next_token(Lexical.TOKEN.CAST); | |
| 270 | ||
| 271 | let type_expression = type_parser.parse(context)!; | |
| 272 | ||
| 273 | context.next_token(Lexical.TOKEN.PAREN_OPEN); | |
| 274 | ||
| 275 | let value = expression_parser.parse(context)!; | |
| 276 | let result = Trees.Expressions.CAST(start::context.location, type_expression, value); | |
| 277 | ||
| 278 | context.next_token(Lexical.TOKEN.PAREN_CLOSE); | |
| 279 | return result; | |
| 280 | si, | |
| 281 | Lexical.TOKEN.CAST | |
| 282 | ); | |
| 283 | ||
| 284 | add_parser( | |
| 285 | (context) is | |
| 286 | let start = context.location; | |
| 287 | context.next_token(Lexical.TOKEN.ISA); | |
| 288 | let type_expression = type_parser.parse(context)!; | |
| 289 | context.next_token(Lexical.TOKEN.PAREN_OPEN); | |
| 290 | let value = expression_parser.parse(context)!; | |
| 291 | let result = Trees.Expressions.ISA(start::context.location, type_expression, value); | |
| 292 | context.next_token(Lexical.TOKEN.PAREN_CLOSE); | |
| 293 | return result; | |
| 294 | si, | |
| 295 | Lexical.TOKEN.ISA | |
| 296 | ); | |
| 297 | ||
| 298 | add_parser( | |
| 299 | (context) is | |
| 300 | let start = context.location; | |
| 301 | context.next_token(Lexical.TOKEN.TYPEOF); | |
| 302 | let type_expression = type_parser.parse(context)!; | |
| 303 | let result = Trees.Expressions.TYPEOF(start::context.location, type_expression); | |
| 304 | return result; | |
| 305 | si, | |
| 306 | Lexical.TOKEN.TYPEOF | |
| 307 | ); | |
| 308 | ||
| 309 | add_parser( | |
| 310 | (context) is | |
| 311 | let location = context.location; | |
| 312 | let value_string = context.current.value_string; | |
| 313 | context.next_token(); | |
| 314 | return Trees.Expressions.Literals.INTEGER(location, value_string); | |
| 315 | si, | |
| 316 | Lexical.TOKEN.INT_LITERAL | |
| 317 | ); | |
| 318 | ||
| 319 | add_parser( | |
| 320 | (context) is | |
| 321 | let location = context.location; | |
| 322 | let value_string = context.current.value_string; | |
| 323 | context.next_token(); | |
| 324 | return Trees.Expressions.Literals.FLOAT(location, value_string); | |
| 325 | si, | |
| 326 | Lexical.TOKEN.FLOAT_LITERAL | |
| 327 | ); | |
| 328 | ||
| 329 | add_parser( | |
| 330 | (context) is | |
| 331 | let location = context.location; | |
| 332 | let value_string = context.current.value_string; | |
| 333 | context.next_token(); | |
| 334 | return Trees.Expressions.Literals.STRING(location, value_string); | |
| 335 | si, | |
| 336 | Lexical.TOKEN.STRING_LITERAL | |
| 337 | ); | |
| 338 | ||
| 339 | add_parser( | |
| 340 | (context) is | |
| 341 | let location = context.location; | |
| 342 | let value_string = context.current.value_string; | |
| 343 | context.next_token(); | |
| 344 | return Trees.Expressions.Literals.CHARACTER(location, value_string); | |
| 345 | si, | |
| 346 | Lexical.TOKEN.CHAR_LITERAL | |
| 347 | ); | |
| 348 | ||
| 349 | add_parser( | |
| 350 | (context) => parse_string_with_interpolations(context), | |
| 351 | Lexical.TOKEN.ENTER_STRING | |
| 352 | ); | |
| 353 | ||
| 354 | add_parser( | |
| 355 | (context) is | |
| 356 | let location = context.location; | |
| 357 | let value_string = context.current.value_string; | |
| 358 | context.next_token(); | |
| 359 | return Trees.Expressions.Literals.BOOLEAN(location, value_string); | |
| 360 | si, | |
| 361 | [Lexical.TOKEN.TRUE, Lexical.TOKEN.FALSE] | |
| 362 | ); | |
| 363 | ||
| 364 | add_parser( | |
| 365 | (context) is | |
| 366 | let location = context.location; | |
| 367 | context.next_token(); | |
| 368 | return Trees.Expressions.NULL(location); | |
| 369 | si, | |
| 370 | Lexical.TOKEN.NULL | |
| 371 | ); | |
| 372 | ||
| 373 | add_parser( | |
| 374 | (context) is | |
| 375 | let location = context.location; | |
| 376 | context.next_token(); | |
| 377 | return Trees.Expressions.SELF(location); | |
| 378 | si, | |
| 379 | Lexical.TOKEN.SELF | |
| 380 | ); | |
| 381 | ||
| 382 | add_parser( | |
| 383 | (context) is | |
| 384 | let location = context.location; | |
| 385 | context.next_token(); | |
| 386 | return Trees.Expressions.SUPER(location); | |
| 387 | si, Lexical.TOKEN.SUPER | |
| 388 | ); | |
| 389 | ||
| 390 | add_parser( | |
| 391 | (context) is | |
| 392 | let location = context.location; | |
| 393 | context.next_token(); | |
| 394 | return Trees.Expressions.RECURSE(location); | |
| 395 | si, Lexical.TOKEN.REC | |
| 396 | ); | |
| 397 | ||
| 398 | add_parser( | |
| 399 | (context) -> Trees.Expressions.Expression is | |
| 400 | let statement = statement_parser.parse(context)!; | |
| 401 | ||
| 402 | return Trees.Expressions.STATEMENT(statement.location, statement); | |
| 403 | si, Lexical.TOKEN.IF | |
| 404 | ); | |
| 405 | ||
| 406 | add_parser( | |
| 407 | (context) -> Trees.Expressions.Expression is | |
| 408 | let statement = statement_parser.parse(context)!; | |
| 409 | ||
| 410 | return Trees.Expressions.STATEMENT(statement.location, statement); | |
| 411 | si, Lexical.TOKEN.CASE | |
| 412 | ); | |
| 413 | ||
| 414 | // `val ... lav` — a value-producing block. The block's | |
| 415 | // value is the LUB of its tail expression (if it provides | |
| 416 | // one) and every `return E` whose target is this block; | |
| 417 | // `return E` inside a `val ... lav` exits the innermost | |
| 418 | // enclosing val-block rather than the enclosing function. | |
| 419 | add_parser( | |
| 420 | (context) -> Trees.Expressions.Expression is | |
| 421 | let start = context.location; | |
| 422 | context.next_token(Lexical.TOKEN.VAL); | |
| 423 | let statements = statement_list_parser.parse(context)!; | |
| 424 | let end = context.location; | |
| 425 | context.next_token(Lexical.TOKEN.LAV, syntax_error_message); | |
| 426 | return Trees.Expressions.VAL_BLOCK(start::end, statements); | |
| 427 | si, Lexical.TOKEN.VAL | |
| 428 | ); | |
| 429 | ||
| 430 | add_parser( | |
| 431 | (context) is | |
| 432 | let start = context.location; | |
| 433 | context.next_token(); | |
| 434 | let want_dispose = false; | |
| 435 | if context.current_token == Lexical.TOKEN.USE then | |
| 436 | // TODO it's not totally clear what the scope of the | |
| 437 | // use should be - just the expression? There may not | |
| 438 | // be a clear statement block given that we're in an | |
| 439 | // expression context | |
| 440 | context.error(context.location, "use is not supported in this context"); | |
| 441 | ||
| 442 | context.next_token(); | |
| 443 | ||
| 444 | // want_dispose = true; | |
| 445 | fi | |
| 446 | ||
| 447 | let variable_list = variable_list_parser.parse(context)!; | |
| 448 | ||
| 449 | let expression = | |
| 450 | if context.next_token(Lexical.TOKEN.IN) then | |
| 451 | expression_parser.parse(context)! | |
| 452 | else | |
| 453 | Trees.Expressions.Literals.NONE(start::variable_list.location) | |
| 454 | fi; | |
| 455 | ||
| 456 | let location = start::expression.location; | |
| 457 | ||
| 458 | return Trees.Expressions.LET_IN( | |
| 459 | location, | |
| 460 | want_dispose, | |
| 461 | variable_list, | |
| 462 | expression | |
| 463 | ); | |
| 464 | si, | |
| 465 | Lexical.TOKEN.LET | |
| 466 | ); | |
| 467 | ||
| 468 | add_parser( | |
| 469 | (context) is | |
| 470 | let start = context.location; | |
| 471 | context.next_token(); | |
| 472 | ||
| 473 | let condition = expression_parser.parse(context)!; | |
| 474 | ||
| 475 | let message: Trees.Expressions.Expression? mut = null; | |
| 476 | ||
| 477 | if context.current_token == Lexical.TOKEN.ELSE then | |
| 478 | context.next_token(); | |
| 479 | message = expression_parser.parse(context); | |
| 480 | fi | |
| 481 | ||
| 482 | let expression = | |
| 483 | if context.next_token(Lexical.TOKEN.IN, syntax_error_message) then | |
| 484 | expression_parser.parse(context)! | |
| 485 | else | |
| 486 | Trees.Expressions.Literals.NONE(start::condition.location) | |
| 487 | fi; | |
| 488 | ||
| 489 | let location = start::expression.location; | |
| 490 | ||
| 491 | return Trees.Expressions.ASSERT_IN( | |
| 492 | location, | |
| 493 | condition, | |
| 494 | message, | |
| 495 | expression | |
| 496 | ); | |
| 497 | si, | |
| 498 | Lexical.TOKEN.ASSERT | |
| 499 | ); | |
| 500 | si | |
| 501 | ||
| 502 | parse_string_with_interpolations(context: CONTEXT) -> Trees.Expressions.Expression is | |
| 503 | // ENTER_STRING expression (':' FORMAT_STRING)? (CONTINUE_STRING expression (':' FORMAT_STRING)? )* (EXIT_STRING | CANCEL_STRING) | |
| 504 | // ^ we're here | |
| 505 | ||
| 506 | let start = context.location; | |
| 507 | ||
| 508 | let fragments = Collections.LIST[Trees.Expressions.INTERPOLATION_FRAGMENT](); | |
| 509 | ||
| 510 | let is_first mut = true; | |
| 511 | let success mut = false; | |
| 512 | let line mut = start.start_line; | |
| 513 | ||
| 514 | while | |
| 515 | context.current_token != Lexical.TOKEN.EXIT_STRING | |
| 516 | do | |
| 517 | // a newline in the string part will result in a CANCEL_STRING token | |
| 518 | // we should stop parsing the string and return immediately | |
| 519 | // TODO: return the interpolation that we've assembled so far | |
| 520 | ||
| 521 | if context.current_token == Lexical.TOKEN.CANCEL_STRING then | |
| 522 | // TODO might want to skip to end of line, as the input could be garbled | |
| 523 | context.next_token(); | |
| 524 | return Trees.Expressions.Literals.STRING(start::context.location, ""); | |
| 525 | fi | |
| 526 | ||
| 527 | // we've either just entered a string interpolation, or we've just passed a closing curly bracket | |
| 528 | // either way we're expecting a string fragment | |
| 529 | ||
| 530 | line = context.location.start_line; | |
| 531 | ||
| 532 | let success_line = parse_single_interpolated_string_fragment(context, is_first, fragments); | |
| 533 | success = success_line.success; | |
| 534 | line = success_line.line; | |
| 535 | ||
| 536 | if !success then | |
| 537 | skip_to_end_of_string_with_interpolations(context, line); | |
| 538 | ||
| 539 | return Trees.Expressions.Literals.STRING(start::context.location, ""); | |
| 540 | fi | |
| 541 | ||
| 542 | if context.current_token == Lexical.TOKEN.CANCEL_STRING then | |
| 543 | // TODO might want to skip to end of line, as the input could be garbled | |
| 544 | context.next_token(); | |
| 545 | return Trees.Expressions.Literals.STRING(start::context.location, ""); | |
| 546 | fi | |
| 547 | ||
| 548 | (success, line) = parse_single_interpolated_expression(context, fragments); | |
| 549 | ||
| 550 | if !success then | |
| 551 | skip_to_end_of_string_with_interpolations(context, line); | |
| 552 | ||
| 553 | return Trees.Expressions.Literals.STRING(start::context.location, ""); | |
| 554 | fi | |
| 555 | ||
| 556 | is_first = false; | |
| 557 | od | |
| 558 | ||
| 559 | if context.current_token == Lexical.TOKEN.CANCEL_STRING then | |
| 560 | context.next_token(); | |
| 561 | elif context.current_token != Lexical.TOKEN.EXIT_STRING then | |
| 562 | context.error(context.location, "unexpected token in string interpolation"); | |
| 563 | ||
| 564 | if context.location.start_line == start.start_line then | |
| 565 | skip_to_end_of_string_with_interpolations(context, line); | |
| 566 | fi | |
| 567 | else | |
| 568 | parse_single_interpolated_string_fragment(context, is_first, fragments); | |
| 569 | fi | |
| 570 | ||
| 571 | let end = context.location; | |
| 572 | ||
| 573 | let expression_count mut = 0; | |
| 574 | let should_poison mut = false; | |
| 575 | let total_fragment_length mut = 0; | |
| 576 | ||
| 577 | for e in fragments do | |
| 578 | if e.is_expression then | |
| 579 | expression_count = expression_count + 1; | |
| 580 | if e.expression.is_poisoned then | |
| 581 | should_poison = true; | |
| 582 | fi | |
| 583 | else | |
| 584 | let fragment = cast Trees.Expressions.Literals.STRING?(e.expression)!; | |
| 585 | let fragment_length = fragment.value_string.length; | |
| 586 | ||
| 587 | total_fragment_length = total_fragment_length + fragment_length; | |
| 588 | fi | |
| 589 | od | |
| 590 | ||
| 591 | let result = Trees.Expressions.STRING_INTERPOLATION(start::end, fragments, total_fragment_length, expression_count); | |
| 592 | ||
| 593 | return result; | |
| 594 | si | |
| 595 | ||
| 596 | skip_to_end_of_string_with_interpolations(context: CONTEXT, line: int) is | |
| 597 | let retries mut = 50; | |
| 598 | ||
| 599 | while | |
| 600 | context.current_token != Lexical.TOKEN.EXIT_STRING /\ | |
| 601 | context.current_token != Lexical.TOKEN.CANCEL_STRING /\ | |
| 602 | context.location.start_line == line /\ | |
| 603 | !context.is_end_of_file /\ | |
| 604 | retries > 0 | |
| 605 | do | |
| 606 | context.next_token(); | |
| 607 | retries = retries - 1; | |
| 608 | od | |
| 609 | si | |
| 610 | ||
| 611 | parse_single_interpolated_string_fragment( | |
| 612 | context: CONTEXT, | |
| 613 | is_first: bool, | |
| 614 | into: Collections.MutableList[Trees.Expressions.INTERPOLATION_FRAGMENT] | |
| 615 | ) -> | |
| 616 | (success: bool, line: int) | |
| 617 | is | |
| 618 | // ENTER_STRING expression (':' FORMAT_STRING)? (CONTINUE_STRING expression (':' FORMAT_STRING)? )* (EXIT_STRING | CANCEL_STRING) | |
| 619 | // ^ we're here ^ or here ^ or here | |
| 620 | ||
| 621 | // we've either just entered a string interpolation, or we've just passed a closing curly bracket | |
| 622 | // either way we're expecting a string fragment | |
| 623 | ||
| 624 | if is_first then | |
| 625 | if !context.expect_token(Lexical.TOKEN.ENTER_STRING) then | |
| 626 | return (false, 0); | |
| 627 | fi | |
| 628 | else | |
| 629 | if | |
| 630 | context.current_token != Lexical.TOKEN.CONTINUE_STRING /\ | |
| 631 | context.current_token != Lexical.TOKEN.EXIT_STRING | |
| 632 | then | |
| 633 | context.logger.error(context.location, "syntax error: expected }} but found {context.current_token_name}"); | |
| 634 | ||
| 635 | return (false, 0); | |
| 636 | fi | |
| 637 | fi | |
| 638 | ||
| 639 | into.add( | |
| 640 | Trees.Expressions.INTERPOLATION_FRAGMENT( | |
| 641 | false, | |
| 642 | Trees.Expressions.Literals.STRING(context.location, context.current_string!), | |
| 643 | null, | |
| 644 | null | |
| 645 | ) | |
| 646 | ); | |
| 647 | ||
| 648 | let line = context.location.start_line; | |
| 649 | ||
| 650 | context.next_token(); | |
| 651 | ||
| 652 | return (true, line); | |
| 653 | si | |
| 654 | ||
| 655 | parse_single_interpolated_expression(context: CONTEXT, into: Collections.MutableList[Trees.Expressions.INTERPOLATION_FRAGMENT]) -> (success: bool, line: int) is | |
| 656 | // ENTER_STRING expression (':' FORMAT_STRING)? (CONTINUE_STRING expression (':' FORMAT_STRING)? )* (EXIT_STRING | CANCEL_STRING) | |
| 657 | // ^ we're here ^ or here | |
| 658 | ||
| 659 | let start = context.location; | |
| 660 | ||
| 661 | let expression: Trees.Expressions.Expression mut; | |
| 662 | ||
| 663 | // Neither an interpolated expression nor the alignment | |
| 664 | // after it is ever a formal-argument list, and the `:` that | |
| 665 | // can follow either opens a format specifier rather than a | |
| 666 | // type. Clear the flag the enclosing expression list may | |
| 667 | // have left set for the whole fragment, so nothing inside | |
| 668 | // it consumes that `:`. | |
| 669 | let previous_allow_tuple_element = context.allow_tuple_element; | |
| 670 | context.allow_tuple_element = false; | |
| 671 | ||
| 672 | if context.current_token != Lexical.TOKEN.CONTINUE_STRING then | |
| 673 | expression = expression_parser.parse(context)!; | |
| 674 | else | |
| 675 | expression = Trees.Expressions.Literals.STRING(context.location, ""); | |
| 676 | context.logger.error(context.location, "expected an expression"); | |
| 677 | context.next_token(); | |
| 678 | fi | |
| 679 | ||
| 680 | if expression.is_poisoned then | |
| 681 | if | |
| 682 | context.current_token != Lexical.TOKEN.COMMA /\ | |
| 683 | context.current_token != Lexical.TOKEN.COLON /\ | |
| 684 | context.current_token != Lexical.TOKEN.CONTINUE_STRING /\ | |
| 685 | context.current_token != Lexical.TOKEN.EXIT_STRING | |
| 686 | then | |
| 687 | context.allow_tuple_element = previous_allow_tuple_element; | |
| 688 | return (false, 0); | |
| 689 | fi | |
| 690 | fi | |
| 691 | ||
| 692 | let alignment: Trees.Expressions.Expression? mut = null; | |
| 693 | let format: string? mut = null; | |
| 694 | ||
| 695 | let line mut = 0; | |
| 696 | ||
| 697 | if context.current_token == Lexical.TOKEN.COMMA then | |
| 698 | context.next_token(); | |
| 699 | ||
| 700 | alignment = expression_parser.parse(context)!; | |
| 701 | ||
| 702 | if alignment.is_poisoned then | |
| 703 | if | |
| 704 | context.current_token != Lexical.TOKEN.COLON /\ | |
| 705 | context.current_token != Lexical.TOKEN.CONTINUE_STRING /\ | |
| 706 | context.current_token != Lexical.TOKEN.EXIT_STRING | |
| 707 | then | |
| 708 | context.allow_tuple_element = previous_allow_tuple_element; | |
| 709 | return (false, 0); | |
| 710 | fi | |
| 711 | fi | |
| 712 | ||
| 713 | line = alignment.location.end_line; | |
| 714 | fi | |
| 715 | ||
| 716 | if context.current_token == Lexical.TOKEN.COLON then | |
| 717 | context.expect_format_specifier(); | |
| 718 | ||
| 719 | context.next_token(); | |
| 720 | ||
| 721 | if context.expect_token(Lexical.TOKEN.FORMAT_STRING) then | |
| 722 | format = context.current_string; | |
| 723 | line = context.location.end_line; | |
| 724 | ||
| 725 | context.next_token(); | |
| 726 | fi | |
| 727 | fi | |
| 728 | ||
| 729 | context.allow_tuple_element = previous_allow_tuple_element; | |
| 730 | ||
| 731 | into.add(Trees.Expressions.INTERPOLATION_FRAGMENT(true, expression, alignment, format)); | |
| 732 | ||
| 733 | return (true, line); | |
| 734 | si | |
| 735 | ||
| 736 | other_token(context: CONTEXT) -> Trees.Expressions.Expression is | |
| 737 | super.other_token(context); | |
| 738 | ||
| 739 | let result = Trees.Expressions.Literals.NONE(context.location); | |
| 740 | ||
| 741 | result.poison(); | |
| 742 | ||
| 743 | return result; | |
| 744 | si | |
| 745 | ||
| 746 | si | |
| 747 | si |