actions-abstract
2 years ago
assets
1 week ago
db-models
2 years ago
export
2 years ago
legacy
2 years ago
meta-boxes
2 years ago
pages
2 years ago
paypal
2 weeks ago
query-views
2 years ago
rest-api
9 months ago
scenarios-abstract
2 years ago
tab-handlers
2 years ago
table-views
2 weeks ago
base-gateway-action.php
1 year ago
base-gateway.php
3 months ago
base-scenario-gateway.php
2 years ago
gateways-editor-data.php
2 weeks ago
legacy-base-gateway.php
2 weeks ago
migrate-legacy-data.php
2 years ago
module.php
2 weeks ago
scenario-item.php
2 years ago
secure-price-notice.php
1 week ago
trusted-price-resolver-expression-parser.php
1 week ago
trusted-price-resolver.php
2 weeks ago
trusted-price-resolver-expression-parser.php
668 lines
| 1 | <?php |
| 2 | |
| 3 | namespace JFB_Modules\Gateways; |
| 4 | |
| 5 | use Jet_Form_Builder\Exceptions\Gateway_Exception; |
| 6 | |
| 7 | // If this file is called directly, abort. |
| 8 | if ( ! defined( 'WPINC' ) ) { |
| 9 | die; |
| 10 | } |
| 11 | |
| 12 | class Trusted_Price_Resolver_Expression_Parser { |
| 13 | |
| 14 | /** |
| 15 | * @var string |
| 16 | */ |
| 17 | private $expression; |
| 18 | |
| 19 | /** |
| 20 | * @var int |
| 21 | */ |
| 22 | private $length; |
| 23 | |
| 24 | /** |
| 25 | * @var int |
| 26 | */ |
| 27 | private $position = 0; |
| 28 | |
| 29 | public function __construct( string $expression ) { |
| 30 | $this->expression = preg_replace( '/\s+/', '', $expression ); |
| 31 | $this->length = strlen( $this->expression ); |
| 32 | } |
| 33 | |
| 34 | /** |
| 35 | * @throws Gateway_Exception |
| 36 | */ |
| 37 | public function parse(): float { |
| 38 | $result = $this->evaluate_node( $this->parse_tree() ); |
| 39 | |
| 40 | if ( ! is_finite( $result ) ) { |
| 41 | throw new Gateway_Exception( 'Calculated price expression produced a non-finite value.' ); |
| 42 | } |
| 43 | |
| 44 | return $result; |
| 45 | } |
| 46 | |
| 47 | /** |
| 48 | * Validate the expression grammar without evaluating its runtime result. |
| 49 | * |
| 50 | * @throws Gateway_Exception |
| 51 | */ |
| 52 | public function validate(): void { |
| 53 | $this->validate_node( $this->parse_tree() ); |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * @throws Gateway_Exception |
| 58 | */ |
| 59 | private function parse_tree(): array { |
| 60 | if ( '' === $this->expression ) { |
| 61 | throw new Gateway_Exception( 'Calculated price expression is empty.' ); |
| 62 | } |
| 63 | |
| 64 | $this->position = 0; |
| 65 | |
| 66 | $tree = $this->parse_conditional(); |
| 67 | |
| 68 | if ( $this->position < $this->length ) { |
| 69 | throw new Gateway_Exception( 'Calculated price expression contains invalid syntax.' ); |
| 70 | } |
| 71 | |
| 72 | return $tree; |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * @throws Gateway_Exception |
| 77 | */ |
| 78 | private function parse_conditional(): array { |
| 79 | $condition = $this->parse_logical_or(); |
| 80 | |
| 81 | if ( ! $this->match( '?' ) ) { |
| 82 | return $condition; |
| 83 | } |
| 84 | |
| 85 | $consequent = $this->parse_conditional(); |
| 86 | |
| 87 | if ( ! $this->match( ':' ) ) { |
| 88 | throw new Gateway_Exception( 'Calculated price expression contains an invalid conditional.' ); |
| 89 | } |
| 90 | |
| 91 | return array( 'conditional', $condition, $consequent, $this->parse_conditional() ); |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * @throws Gateway_Exception |
| 96 | */ |
| 97 | private function parse_logical_or(): array { |
| 98 | $node = $this->parse_logical_and(); |
| 99 | |
| 100 | while ( $this->match( '||' ) ) { |
| 101 | $node = array( 'binary', '||', $node, $this->parse_logical_and() ); |
| 102 | } |
| 103 | |
| 104 | return $node; |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * @throws Gateway_Exception |
| 109 | */ |
| 110 | private function parse_logical_and(): array { |
| 111 | $node = $this->parse_bitwise_xor(); |
| 112 | |
| 113 | while ( $this->match( '&&' ) ) { |
| 114 | $node = array( 'binary', '&&', $node, $this->parse_bitwise_xor() ); |
| 115 | } |
| 116 | |
| 117 | return $node; |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Match JavaScript operator precedence: equality binds before bitwise XOR, |
| 122 | * while logical AND binds after it. |
| 123 | * |
| 124 | * @throws Gateway_Exception |
| 125 | */ |
| 126 | private function parse_bitwise_xor(): array { |
| 127 | $node = $this->parse_equality(); |
| 128 | |
| 129 | while ( $this->match( '^' ) ) { |
| 130 | $node = array( 'binary', '^', $node, $this->parse_equality() ); |
| 131 | } |
| 132 | |
| 133 | return $node; |
| 134 | } |
| 135 | |
| 136 | /** |
| 137 | * @throws Gateway_Exception |
| 138 | */ |
| 139 | private function parse_equality(): array { |
| 140 | $node = $this->parse_comparison(); |
| 141 | |
| 142 | while ( true ) { |
| 143 | $operator = $this->match_any( array( '===', '!==', '==', '!=' ) ); |
| 144 | |
| 145 | if ( false === $operator ) { |
| 146 | return $node; |
| 147 | } |
| 148 | |
| 149 | $node = array( 'binary', $operator, $node, $this->parse_comparison() ); |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | /** |
| 154 | * @throws Gateway_Exception |
| 155 | */ |
| 156 | private function parse_comparison(): array { |
| 157 | $node = $this->parse_expression(); |
| 158 | |
| 159 | while ( true ) { |
| 160 | $operator = $this->match_any( array( '<=', '>=', '<', '>' ) ); |
| 161 | |
| 162 | if ( false === $operator ) { |
| 163 | return $node; |
| 164 | } |
| 165 | |
| 166 | $node = array( 'binary', $operator, $node, $this->parse_expression() ); |
| 167 | } |
| 168 | } |
| 169 | |
| 170 | /** |
| 171 | * @throws Gateway_Exception |
| 172 | */ |
| 173 | private function parse_expression(): array { |
| 174 | $node = $this->parse_term(); |
| 175 | |
| 176 | while ( true ) { |
| 177 | $operator = $this->match_any( array( '+', '-' ) ); |
| 178 | |
| 179 | if ( false === $operator ) { |
| 180 | return $node; |
| 181 | } |
| 182 | |
| 183 | $node = array( 'binary', $operator, $node, $this->parse_term() ); |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | /** |
| 188 | * @throws Gateway_Exception |
| 189 | */ |
| 190 | private function parse_term(): array { |
| 191 | $node = $this->parse_power(); |
| 192 | |
| 193 | while ( true ) { |
| 194 | if ( '*' === $this->peek() && '*' === $this->peek( 1 ) ) { |
| 195 | return $node; |
| 196 | } |
| 197 | |
| 198 | $operator = $this->match_any( array( '*', '/', '%' ) ); |
| 199 | |
| 200 | if ( false === $operator ) { |
| 201 | return $node; |
| 202 | } |
| 203 | |
| 204 | $node = array( 'binary', $operator, $node, $this->parse_power() ); |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | /** |
| 209 | * @throws Gateway_Exception |
| 210 | */ |
| 211 | private function parse_power(): array { |
| 212 | $node = $this->parse_factor(); |
| 213 | |
| 214 | if ( $this->match( '**' ) ) { |
| 215 | $node = array( 'binary', '**', $node, $this->parse_power() ); |
| 216 | } |
| 217 | |
| 218 | return $node; |
| 219 | } |
| 220 | |
| 221 | /** |
| 222 | * @throws Gateway_Exception |
| 223 | */ |
| 224 | private function parse_factor(): array { |
| 225 | $operator = $this->peek(); |
| 226 | |
| 227 | if ( '+' === $operator || '-' === $operator || '!' === $operator ) { |
| 228 | ++$this->position; |
| 229 | |
| 230 | return array( 'unary', $operator, $this->parse_factor() ); |
| 231 | } |
| 232 | |
| 233 | if ( '(' === $operator ) { |
| 234 | ++$this->position; |
| 235 | $node = $this->parse_conditional(); |
| 236 | |
| 237 | if ( ')' !== $this->peek() ) { |
| 238 | throw new Gateway_Exception( 'Calculated price expression contains unbalanced parentheses.' ); |
| 239 | } |
| 240 | |
| 241 | ++$this->position; |
| 242 | |
| 243 | return $node; |
| 244 | } |
| 245 | |
| 246 | if ( false !== $operator && preg_match( '/[a-zA-Z_]/', $operator ) ) { |
| 247 | return $this->parse_identifier(); |
| 248 | } |
| 249 | |
| 250 | return $this->parse_number(); |
| 251 | } |
| 252 | |
| 253 | /** |
| 254 | * @throws Gateway_Exception |
| 255 | */ |
| 256 | private function parse_number(): array { |
| 257 | $remaining = substr( $this->expression, $this->position ); |
| 258 | |
| 259 | if ( ! preg_match( '/^(?:(?:[0-9]+(?:\.[0-9]*)?)|(?:\.[0-9]+))(?:[eE][+-]?[0-9]+)?/', $remaining, $matches ) ) { |
| 260 | throw new Gateway_Exception( 'Calculated price expression contains an invalid token.' ); |
| 261 | } |
| 262 | |
| 263 | $number = $matches[0]; |
| 264 | $this->position += strlen( $number ); |
| 265 | |
| 266 | if ( ! is_numeric( $number ) ) { |
| 267 | throw new Gateway_Exception( 'Calculated price expression contains an invalid number.' ); |
| 268 | } |
| 269 | |
| 270 | return array( 'number', (float) $number ); |
| 271 | } |
| 272 | |
| 273 | /** |
| 274 | * @throws Gateway_Exception |
| 275 | */ |
| 276 | private function parse_identifier(): array { |
| 277 | $remaining = substr( $this->expression, $this->position ); |
| 278 | |
| 279 | if ( ! preg_match( '/^[a-zA-Z_][a-zA-Z0-9_]*(?:\.[a-zA-Z_][a-zA-Z0-9_]*)?/', $remaining, $matches ) ) { |
| 280 | throw new Gateway_Exception( 'Calculated price expression contains an invalid identifier.' ); |
| 281 | } |
| 282 | |
| 283 | $name = $matches[0]; |
| 284 | $this->position += strlen( $name ); |
| 285 | |
| 286 | if ( ! $this->match( '(' ) ) { |
| 287 | return array( 'constant', $name ); |
| 288 | } |
| 289 | |
| 290 | $arguments = array(); |
| 291 | |
| 292 | if ( ! $this->match( ')' ) ) { |
| 293 | do { |
| 294 | $arguments[] = $this->parse_conditional(); |
| 295 | } while ( $this->match( ',' ) ); |
| 296 | |
| 297 | if ( ! $this->match( ')' ) ) { |
| 298 | throw new Gateway_Exception( 'Calculated price expression contains an invalid function call.' ); |
| 299 | } |
| 300 | } |
| 301 | |
| 302 | return array( 'call', $name, $arguments ); |
| 303 | } |
| 304 | |
| 305 | /** |
| 306 | * @throws Gateway_Exception |
| 307 | */ |
| 308 | private function evaluate_node( array $node ): float { |
| 309 | switch ( $node[0] ) { |
| 310 | case 'number': |
| 311 | return $node[1]; |
| 312 | |
| 313 | case 'constant': |
| 314 | return $this->evaluate_constant( $node[1] ); |
| 315 | |
| 316 | case 'call': |
| 317 | return $this->evaluate_math_call( $node[1], $node[2] ); |
| 318 | |
| 319 | case 'unary': |
| 320 | $value = $this->evaluate_node( $node[2] ); |
| 321 | |
| 322 | if ( '!' === $node[1] ) { |
| 323 | return $this->is_truthy( $value ) ? 0.0 : 1.0; |
| 324 | } |
| 325 | |
| 326 | return '-' === $node[1] ? -1 * $value : $value; |
| 327 | |
| 328 | case 'conditional': |
| 329 | return $this->is_truthy( $this->evaluate_node( $node[1] ) ) |
| 330 | ? $this->evaluate_node( $node[2] ) |
| 331 | : $this->evaluate_node( $node[3] ); |
| 332 | |
| 333 | case 'binary': |
| 334 | return $this->evaluate_binary( $node[1], $node[2], $node[3] ); |
| 335 | } |
| 336 | |
| 337 | throw new Gateway_Exception( 'Calculated price expression contains an invalid node.' ); |
| 338 | } |
| 339 | |
| 340 | /** |
| 341 | * @throws Gateway_Exception |
| 342 | */ |
| 343 | private function validate_node( array $node ): void { |
| 344 | switch ( $node[0] ) { |
| 345 | case 'number': |
| 346 | return; |
| 347 | |
| 348 | case 'constant': |
| 349 | $this->assert_supported_constant( $node[1] ); |
| 350 | return; |
| 351 | |
| 352 | case 'call': |
| 353 | $this->assert_supported_math_call( $node[1], $node[2] ); |
| 354 | |
| 355 | foreach ( $node[2] as $argument ) { |
| 356 | $this->validate_node( $argument ); |
| 357 | } |
| 358 | return; |
| 359 | |
| 360 | case 'unary': |
| 361 | $this->validate_node( $node[2] ); |
| 362 | return; |
| 363 | |
| 364 | case 'conditional': |
| 365 | $this->validate_node( $node[1] ); |
| 366 | $this->validate_node( $node[2] ); |
| 367 | $this->validate_node( $node[3] ); |
| 368 | return; |
| 369 | |
| 370 | case 'binary': |
| 371 | $this->validate_node( $node[2] ); |
| 372 | $this->validate_node( $node[3] ); |
| 373 | return; |
| 374 | } |
| 375 | |
| 376 | throw new Gateway_Exception( 'Calculated price expression contains an invalid node.' ); |
| 377 | } |
| 378 | |
| 379 | /** |
| 380 | * @throws Gateway_Exception |
| 381 | */ |
| 382 | private function evaluate_binary( string $operator, array $left_node, array $right_node ): float { |
| 383 | $left = $this->evaluate_node( $left_node ); |
| 384 | |
| 385 | if ( '&&' === $operator ) { |
| 386 | return $this->is_truthy( $left ) ? $this->evaluate_node( $right_node ) : $left; |
| 387 | } |
| 388 | |
| 389 | if ( '||' === $operator ) { |
| 390 | return $this->is_truthy( $left ) ? $left : $this->evaluate_node( $right_node ); |
| 391 | } |
| 392 | |
| 393 | $right = $this->evaluate_node( $right_node ); |
| 394 | |
| 395 | switch ( $operator ) { |
| 396 | case '+': |
| 397 | return $left + $right; |
| 398 | |
| 399 | case '-': |
| 400 | return $left - $right; |
| 401 | |
| 402 | case '*': |
| 403 | return $left * $right; |
| 404 | |
| 405 | case '/': |
| 406 | if ( 0.0 === $right ) { |
| 407 | throw new Gateway_Exception( 'Calculated price expression attempted division by zero.' ); |
| 408 | } |
| 409 | |
| 410 | return $left / $right; |
| 411 | |
| 412 | case '%': |
| 413 | if ( 0.0 === $right ) { |
| 414 | throw new Gateway_Exception( 'Calculated price expression attempted modulo by zero.' ); |
| 415 | } |
| 416 | |
| 417 | return fmod( $left, $right ); |
| 418 | |
| 419 | case '**': |
| 420 | return $left ** $right; |
| 421 | |
| 422 | case '^': |
| 423 | return (float) ( $this->to_int32( $left ) ^ $this->to_int32( $right ) ); |
| 424 | |
| 425 | case '<': |
| 426 | return $left < $right ? 1.0 : 0.0; |
| 427 | |
| 428 | case '<=': |
| 429 | return $left <= $right ? 1.0 : 0.0; |
| 430 | |
| 431 | case '>': |
| 432 | return $left > $right ? 1.0 : 0.0; |
| 433 | |
| 434 | case '>=': |
| 435 | return $left >= $right ? 1.0 : 0.0; |
| 436 | |
| 437 | case '==': |
| 438 | case '===': |
| 439 | return $left === $right ? 1.0 : 0.0; |
| 440 | |
| 441 | case '!=': |
| 442 | case '!==': |
| 443 | return $left !== $right ? 1.0 : 0.0; |
| 444 | } |
| 445 | |
| 446 | throw new Gateway_Exception( 'Calculated price expression contains an unsupported operator.' ); |
| 447 | } |
| 448 | |
| 449 | /** |
| 450 | * Reproduce JavaScript ToInt32 conversion used by bitwise operators. |
| 451 | */ |
| 452 | private function to_int32( float $value ): int { |
| 453 | if ( ! is_finite( $value ) || 0.0 === $value ) { |
| 454 | return 0; |
| 455 | } |
| 456 | |
| 457 | $integer = $value < 0 ? ceil( $value ) : floor( $value ); |
| 458 | $uint32 = fmod( $integer, 4294967296.0 ); |
| 459 | |
| 460 | if ( $uint32 < 0 ) { |
| 461 | $uint32 += 4294967296.0; |
| 462 | } |
| 463 | |
| 464 | if ( $uint32 >= 2147483648.0 ) { |
| 465 | $uint32 -= 4294967296.0; |
| 466 | } |
| 467 | |
| 468 | return (int) $uint32; |
| 469 | } |
| 470 | |
| 471 | /** |
| 472 | * @throws Gateway_Exception |
| 473 | */ |
| 474 | private function evaluate_constant( string $name ): float { |
| 475 | $constants = $this->get_supported_constants(); |
| 476 | |
| 477 | $this->assert_supported_constant( $name ); |
| 478 | |
| 479 | return (float) $constants[ $name ]; |
| 480 | } |
| 481 | |
| 482 | private function get_supported_constants(): array { |
| 483 | return array( |
| 484 | 'true' => 1.0, |
| 485 | 'false' => 0.0, |
| 486 | 'Math.E' => M_E, |
| 487 | 'Math.LN2' => M_LN2, |
| 488 | 'Math.LN10' => M_LN10, |
| 489 | 'Math.LOG2E' => M_LOG2E, |
| 490 | 'Math.LOG10E' => M_LOG10E, |
| 491 | 'Math.PI' => M_PI, |
| 492 | 'Math.SQRT1_2' => M_SQRT1_2, |
| 493 | 'Math.SQRT2' => M_SQRT2, |
| 494 | ); |
| 495 | } |
| 496 | |
| 497 | /** |
| 498 | * @throws Gateway_Exception |
| 499 | */ |
| 500 | private function assert_supported_constant( string $name ): void { |
| 501 | if ( ! array_key_exists( $name, $this->get_supported_constants() ) ) { |
| 502 | throw new Gateway_Exception( 'Calculated price expression contains an unsupported identifier.' ); |
| 503 | } |
| 504 | } |
| 505 | |
| 506 | /** |
| 507 | * @throws Gateway_Exception |
| 508 | */ |
| 509 | private function evaluate_math_call( string $name, array $argument_nodes ): float { |
| 510 | $this->assert_supported_math_call( $name, $argument_nodes ); |
| 511 | |
| 512 | $arguments = array_map( |
| 513 | function ( $node ) { |
| 514 | return $this->evaluate_node( $node ); |
| 515 | }, |
| 516 | $argument_nodes |
| 517 | ); |
| 518 | |
| 519 | switch ( $name ) { |
| 520 | case 'Math.abs': |
| 521 | $result = abs( $arguments[0] ); |
| 522 | break; |
| 523 | |
| 524 | case 'Math.ceil': |
| 525 | $result = ceil( $arguments[0] ); |
| 526 | break; |
| 527 | |
| 528 | case 'Math.floor': |
| 529 | $result = floor( $arguments[0] ); |
| 530 | break; |
| 531 | |
| 532 | case 'Math.round': |
| 533 | $result = $this->js_math_round( $arguments[0] ); |
| 534 | break; |
| 535 | |
| 536 | case 'Math.trunc': |
| 537 | $result = $arguments[0] < 0 ? ceil( $arguments[0] ) : floor( $arguments[0] ); |
| 538 | break; |
| 539 | |
| 540 | case 'Math.sign': |
| 541 | $result = $arguments[0] <=> 0; |
| 542 | break; |
| 543 | |
| 544 | case 'Math.sqrt': |
| 545 | $result = sqrt( $arguments[0] ); |
| 546 | break; |
| 547 | |
| 548 | case 'Math.pow': |
| 549 | $result = $arguments[0] ** $arguments[1]; |
| 550 | break; |
| 551 | |
| 552 | case 'Math.min': |
| 553 | $result = min( $arguments ); |
| 554 | break; |
| 555 | |
| 556 | case 'Math.max': |
| 557 | $result = max( $arguments ); |
| 558 | break; |
| 559 | |
| 560 | default: |
| 561 | throw new Gateway_Exception( 'Calculated price expression contains an unsupported function.' ); |
| 562 | } |
| 563 | |
| 564 | if ( ! is_finite( (float) $result ) ) { |
| 565 | throw new Gateway_Exception( 'Calculated price expression produced a non-finite value.' ); |
| 566 | } |
| 567 | |
| 568 | return (float) $result; |
| 569 | } |
| 570 | |
| 571 | /** |
| 572 | * @throws Gateway_Exception |
| 573 | */ |
| 574 | private function assert_supported_math_call( string $name, array $arguments ): void { |
| 575 | switch ( $name ) { |
| 576 | case 'Math.abs': |
| 577 | case 'Math.ceil': |
| 578 | case 'Math.floor': |
| 579 | case 'Math.round': |
| 580 | case 'Math.trunc': |
| 581 | case 'Math.sign': |
| 582 | case 'Math.sqrt': |
| 583 | $this->assert_argument_count( $name, $arguments, 1 ); |
| 584 | return; |
| 585 | |
| 586 | case 'Math.pow': |
| 587 | $this->assert_argument_count( $name, $arguments, 2 ); |
| 588 | return; |
| 589 | |
| 590 | case 'Math.min': |
| 591 | case 'Math.max': |
| 592 | $this->assert_argument_count( $name, $arguments, 1, PHP_INT_MAX ); |
| 593 | return; |
| 594 | } |
| 595 | |
| 596 | throw new Gateway_Exception( 'Calculated price expression contains an unsupported function.' ); |
| 597 | } |
| 598 | |
| 599 | /** |
| 600 | * Reproduce JavaScript Math.round: round half toward +Infinity. |
| 601 | * |
| 602 | * Calling floor( $value + 0.5 ) diverges for values just below .5 (e.g. |
| 603 | * 0.49999999999999994), where forming $value + 0.5 rounds up to 1.0 and |
| 604 | * over-rounds. Comparing the fractional part against 0.5 avoids that. |
| 605 | */ |
| 606 | private function js_math_round( float $value ): float { |
| 607 | $floor = floor( $value ); |
| 608 | $fraction = $value - $floor; |
| 609 | |
| 610 | return $fraction >= 0.5 ? $floor + 1.0 : $floor; |
| 611 | } |
| 612 | |
| 613 | /** |
| 614 | * @throws Gateway_Exception |
| 615 | */ |
| 616 | private function assert_argument_count( |
| 617 | string $name, |
| 618 | array $arguments, |
| 619 | int $minimum, |
| 620 | ?int $maximum = null |
| 621 | ): void { |
| 622 | $maximum = null === $maximum ? $minimum : $maximum; |
| 623 | $count = count( $arguments ); |
| 624 | |
| 625 | if ( $count < $minimum || $count > $maximum ) { |
| 626 | throw new Gateway_Exception( |
| 627 | sprintf( |
| 628 | 'The "%1$s" function has an invalid number of arguments.', |
| 629 | esc_html( $name ) |
| 630 | ) |
| 631 | ); |
| 632 | } |
| 633 | } |
| 634 | |
| 635 | private function is_truthy( float $value ): bool { |
| 636 | return 0.0 !== $value && ! is_nan( $value ); |
| 637 | } |
| 638 | |
| 639 | private function match( string $token ): bool { |
| 640 | if ( substr( $this->expression, $this->position, strlen( $token ) ) !== $token ) { |
| 641 | return false; |
| 642 | } |
| 643 | |
| 644 | $this->position += strlen( $token ); |
| 645 | |
| 646 | return true; |
| 647 | } |
| 648 | |
| 649 | /** |
| 650 | * @return false|string |
| 651 | */ |
| 652 | private function match_any( array $tokens ) { |
| 653 | foreach ( $tokens as $token ) { |
| 654 | if ( $this->match( $token ) ) { |
| 655 | return $token; |
| 656 | } |
| 657 | } |
| 658 | |
| 659 | return false; |
| 660 | } |
| 661 | |
| 662 | private function peek( int $offset = 0 ) { |
| 663 | $position = $this->position + $offset; |
| 664 | |
| 665 | return $position < $this->length ? $this->expression[ $position ] : false; |
| 666 | } |
| 667 | } |
| 668 |