lib/scssphp/Parser.php

   1 <?php
   2 /**
   3  * SCSSPHP
   4  *
   5  * @copyright 2012-2019 Leaf Corcoran
   6  *
   7  * @license http://opensource.org/licenses/MIT MIT
   8  *
   9  * @link http://scssphp.github.io/scssphp
  10  */
  11
  12 namespace ScssPhp\ScssPhp;
  13
  14 use ScssPhp\ScssPhp\Block;
  15 use ScssPhp\ScssPhp\Cache;
  16 use ScssPhp\ScssPhp\Compiler;
  17 use ScssPhp\ScssPhp\Exception\ParserException;
  18 use ScssPhp\ScssPhp\Node;
  19 use ScssPhp\ScssPhp\Type;
  20
  21 /**
  22  * Parser
  23  *
  24  * @author Leaf Corcoran <leafot@gmail.com>
  25  */
  26 class Parser
  27 {
  28     const SOURCE_INDEX  = -1;
  29     const SOURCE_LINE   = -2;
  30     const SOURCE_COLUMN = -3;
  31
  32     /**
  33      * @var array
  34      */
  35     protected static $precedence = [
  36         '='   => 0,
  37         'or'  => 1,
  38         'and' => 2,
  39         '=='  => 3,
  40         '!='  => 3,
  41         '<=>' => 3,
  42         '<='  => 4,
  43         '>='  => 4,
  44         '<'   => 4,
  45         '>'   => 4,
  46         '+'   => 5,
  47         '-'   => 5,
  48         '*'   => 6,
  49         '/'   => 6,
  50         '%'   => 6,
  51     ];
  52
  53     protected static $commentPattern;
  54     protected static $operatorPattern;
  55     protected static $whitePattern;
  56
  57     protected $cache;
  58
  59     private $sourceName;
  60     private $sourceIndex;
  61     private $sourcePositions;
  62     private $charset;
  63     private $count;
  64     private $env;
  65     private $inParens;
  66     private $eatWhiteDefault;
  67     private $discardComments;
  68     private $buffer;
  69     private $utf8;
  70     private $encoding;
  71     private $patternModifiers;
  72     private $commentsSeen;
  73
  74     /**
  75      * Constructor
  76      *
  77      * @api
  78      *
  79      * @param string                 $sourceName
  80      * @param integer                $sourceIndex
  81      * @param string                 $encoding
  82      * @param \ScssPhp\ScssPhp\Cache $cache
  83      */
  84     public function __construct($sourceName, $sourceIndex = 0, $encoding = 'utf-8', $cache = null)
  85     {
  86         $this->sourceName       = $sourceName ?: '(stdin)';
  87         $this->sourceIndex      = $sourceIndex;
  88         $this->charset          = null;
  89         $this->utf8             = ! $encoding || strtolower($encoding) === 'utf-8';
  90         $this->patternModifiers = $this->utf8 ? 'Aisu' : 'Ais';
  91         $this->commentsSeen     = [];
  92         $this->discardComments  = false;
  93
  94         if (empty(static::$operatorPattern)) {
  95             static::$operatorPattern = '([*\/%+-]|[!=]\=|\>\=?|\<\=\>|\<\=?|and|or)';
  96
  97             $commentSingle      = '\/\/';
  98             $commentMultiLeft   = '\/\*';
  99             $commentMultiRight  = '\*\/';
 100
 101             static::$commentPattern = $commentMultiLeft . '.*?' . $commentMultiRight;
 102             static::$whitePattern = $this->utf8
 103                 ? '/' . $commentSingle . '[^\n]*\s*|(' . static::$commentPattern . ')\s*|\s+/AisuS'
 104                 : '/' . $commentSingle . '[^\n]*\s*|(' . static::$commentPattern . ')\s*|\s+/AisS';
 105         }
 106
 107         if ($cache) {
 108             $this->cache = $cache;
 109         }
 110     }
 111
 112     /**
 113      * Get source file name
 114      *
 115      * @api
 116      *
 117      * @return string
 118      */
 119     public function getSourceName()
 120     {
 121         return $this->sourceName;
 122     }
 123
 124     /**
 125      * Throw parser error
 126      *
 127      * @api
 128      *
 129      * @param string $msg
 130      *
 131      * @throws \ScssPhp\ScssPhp\Exception\ParserException
 132      */
 133     public function throwParseError($msg = 'parse error')
 134     {
 135         list($line, $column) = $this->getSourcePosition($this->count);
 136
 137         $loc = empty($this->sourceName)
 138              ? "line: $line, column: $column"
 139              : "$this->sourceName on line $line, at column $column";
 140
 141         if ($this->peek("(.*?)(\n|$)", $m, $this->count)) {
 142             throw new ParserException("$msg: failed at `$m[1]` $loc");
 143         }
 144
 145         throw new ParserException("$msg: $loc");
 146     }
 147
 148     /**
 149      * Parser buffer
 150      *
 151      * @api
 152      *
 153      * @param string $buffer
 154      *
 155      * @return \ScssPhp\ScssPhp\Block
 156      */
 157     public function parse($buffer)
 158     {
 159         if ($this->cache) {
 160             $cacheKey = $this->sourceName . ":" . md5($buffer);
 161             $parseOptions = [
 162                 'charset' => $this->charset,
 163                 'utf8' => $this->utf8,
 164             ];
 165             $v = $this->cache->getCache("parse", $cacheKey, $parseOptions);
 166
 167             if (! is_null($v)) {
 168                 return $v;
 169             }
 170         }
 171
 172         // strip BOM (byte order marker)
 173         if (substr($buffer, 0, 3) === "\xef\xbb\xbf") {
 174             $buffer = substr($buffer, 3);
 175         }
 176
 177         $this->buffer          = rtrim($buffer, "\x00..\x1f");
 178         $this->count           = 0;
 179         $this->env             = null;
 180         $this->inParens        = false;
 181         $this->eatWhiteDefault = true;
 182
 183         $this->saveEncoding();
 184         $this->extractLineNumbers($buffer);
 185
 186         $this->pushBlock(null); // root block
 187         $this->whitespace();
 188         $this->pushBlock(null);
 189         $this->popBlock();
 190
 191         while ($this->parseChunk()) {
 192             ;
 193         }
 194
 195         if ($this->count !== strlen($this->buffer)) {
 196             $this->throwParseError();
 197         }
 198
 199         if (! empty($this->env->parent)) {
 200             $this->throwParseError('unclosed block');
 201         }
 202
 203         if ($this->charset) {
 204             array_unshift($this->env->children, $this->charset);
 205         }
 206
 207         $this->restoreEncoding();
 208
 209         if ($this->cache) {
 210             $this->cache->setCache("parse", $cacheKey, $this->env, $parseOptions);
 211         }
 212
 213         return $this->env;
 214     }
 215
 216     /**
 217      * Parse a value or value list
 218      *
 219      * @api
 220      *
 221      * @param string       $buffer
 222      * @param string|array $out
 223      *
 224      * @return boolean
 225      */
 226     public function parseValue($buffer, &$out)
 227     {
 228         $this->count           = 0;
 229         $this->env             = null;
 230         $this->inParens        = false;
 231         $this->eatWhiteDefault = true;
 232         $this->buffer          = (string) $buffer;
 233
 234         $this->saveEncoding();
 235
 236         $list = $this->valueList($out);
 237
 238         $this->restoreEncoding();
 239
 240         return $list;
 241     }
 242
 243     /**
 244      * Parse a selector or selector list
 245      *
 246      * @api
 247      *
 248      * @param string       $buffer
 249      * @param string|array $out
 250      *
 251      * @return boolean
 252      */
 253     public function parseSelector($buffer, &$out)
 254     {
 255         $this->count           = 0;
 256         $this->env             = null;
 257         $this->inParens        = false;
 258         $this->eatWhiteDefault = true;
 259         $this->buffer          = (string) $buffer;
 260
 261         $this->saveEncoding();
 262
 263         $selector = $this->selectors($out);
 264
 265         $this->restoreEncoding();
 266
 267         return $selector;
 268     }
 269
 270     /**
 271      * Parse a media Query
 272      *
 273      * @api
 274      *
 275      * @param string       $buffer
 276      * @param string|array $out
 277      *
 278      * @return boolean
 279      */
 280     public function parseMediaQueryList($buffer, &$out)
 281     {
 282         $this->count           = 0;
 283         $this->env             = null;
 284         $this->inParens        = false;
 285         $this->eatWhiteDefault = true;
 286         $this->buffer          = (string) $buffer;
 287
 288         $this->saveEncoding();
 289
 290         $isMediaQuery = $this->mediaQueryList($out);
 291
 292         $this->restoreEncoding();
 293
 294         return $isMediaQuery;
 295     }
 296
 297     /**
 298      * Parse a single chunk off the head of the buffer and append it to the
 299      * current parse environment.
 300      *
 301      * Returns false when the buffer is empty, or when there is an error.
 302      *
 303      * This function is called repeatedly until the entire document is
 304      * parsed.
 305      *
 306      * This parser is most similar to a recursive descent parser. Single
 307      * functions represent discrete grammatical rules for the language, and
 308      * they are able to capture the text that represents those rules.
 309      *
 310      * Consider the function Compiler::keyword(). (All parse functions are
 311      * structured the same.)
 312      *
 313      * The function takes a single reference argument. When calling the
 314      * function it will attempt to match a keyword on the head of the buffer.
 315      * If it is successful, it will place the keyword in the referenced
 316      * argument, advance the position in the buffer, and return true. If it
 317      * fails then it won't advance the buffer and it will return false.
 318      *
 319      * All of these parse functions are powered by Compiler::match(), which behaves
 320      * the same way, but takes a literal regular expression. Sometimes it is
 321      * more convenient to use match instead of creating a new function.
 322      *
 323      * Because of the format of the functions, to parse an entire string of
 324      * grammatical rules, you can chain them together using &&.
 325      *
 326      * But, if some of the rules in the chain succeed before one fails, then
 327      * the buffer position will be left at an invalid state. In order to
 328      * avoid this, Compiler::seek() is used to remember and set buffer positions.
 329      *
 330      * Before parsing a chain, use $s = $this->count to remember the current
 331      * position into $s. Then if a chain fails, use $this->seek($s) to
 332      * go back where we started.
 333      *
 334      * @return boolean
 335      */
 336     protected function parseChunk()
 337     {
 338         $s = $this->count;
 339
 340         // the directives
 341         if (isset($this->buffer[$this->count]) && $this->buffer[$this->count] === '@') {
 342             if ($this->literal('@at-root', 8) &&
 343                 ($this->selectors($selector) || true) &&
 344                 ($this->map($with) || true) &&
 345                 (($this->matchChar('(')
 346                     && $this->interpolation($with)
 347                     && $this->matchChar(')')) || true) &&
 348                 $this->matchChar('{', false)
 349             ) {
 350                 $atRoot = $this->pushSpecialBlock(Type::T_AT_ROOT, $s);
 351                 $atRoot->selector = $selector;
 352                 $atRoot->with     = $with;
 353
 354                 return true;
 355             }
 356
 357             $this->seek($s);
 358
 359             if ($this->literal('@media', 6) && $this->mediaQueryList($mediaQueryList) && $this->matchChar('{', false)) {
 360                 $media = $this->pushSpecialBlock(Type::T_MEDIA, $s);
 361                 $media->queryList = $mediaQueryList[2];
 362
 363                 return true;
 364             }
 365
 366             $this->seek($s);
 367
 368             if ($this->literal('@mixin', 6) &&
 369                 $this->keyword($mixinName) &&
 370                 ($this->argumentDef($args) || true) &&
 371                 $this->matchChar('{', false)
 372             ) {
 373                 $mixin = $this->pushSpecialBlock(Type::T_MIXIN, $s);
 374                 $mixin->name = $mixinName;
 375                 $mixin->args = $args;
 376
 377                 return true;
 378             }
 379
 380             $this->seek($s);
 381
 382             if ($this->literal('@include', 8) &&
 383                 $this->keyword($mixinName) &&
 384                 ($this->matchChar('(') &&
 385                     ($this->argValues($argValues) || true) &&
 386                     $this->matchChar(')') || true) &&
 387                 ($this->end() ||
 388                     ($this->literal('using', 5) &&
 389                         $this->argumentDef($argUsing) &&
 390                         ($this->end() || $this->matchChar('{') && $hasBlock = true)) ||
 391                     $this->matchChar('{') && $hasBlock = true)
 392             ) {
 393                 $child = [
 394                     Type::T_INCLUDE,
 395                     $mixinName,
 396                     isset($argValues) ? $argValues : null,
 397                     null,
 398                     isset($argUsing) ? $argUsing : null
 399                 ];
 400
 401                 if (! empty($hasBlock)) {
 402                     $include = $this->pushSpecialBlock(Type::T_INCLUDE, $s);
 403                     $include->child = $child;
 404                 } else {
 405                     $this->append($child, $s);
 406                 }
 407
 408                 return true;
 409             }
 410
 411             $this->seek($s);
 412
 413             if ($this->literal('@scssphp-import-once', 20) &&
 414                 $this->valueList($importPath) &&
 415                 $this->end()
 416             ) {
 417                 $this->append([Type::T_SCSSPHP_IMPORT_ONCE, $importPath], $s);
 418
 419                 return true;
 420             }
 421
 422             $this->seek($s);
 423
 424             if ($this->literal('@import', 7) &&
 425                 $this->valueList($importPath) &&
 426                 $this->end()
 427             ) {
 428                 $this->append([Type::T_IMPORT, $importPath], $s);
 429
 430                 return true;
 431             }
 432
 433             $this->seek($s);
 434
 435             if ($this->literal('@import', 7) &&
 436                 $this->url($importPath) &&
 437                 $this->end()
 438             ) {
 439                 $this->append([Type::T_IMPORT, $importPath], $s);
 440
 441                 return true;
 442             }
 443
 444             $this->seek($s);
 445
 446             if ($this->literal('@extend', 7) &&
 447                 $this->selectors($selectors) &&
 448                 $this->end()
 449             ) {
 450                 // check for '!flag'
 451                 $optional = $this->stripOptionalFlag($selectors);
 452                 $this->append([Type::T_EXTEND, $selectors, $optional], $s);
 453
 454                 return true;
 455             }
 456
 457             $this->seek($s);
 458
 459             if ($this->literal('@function', 9) &&
 460                 $this->keyword($fnName) &&
 461                 $this->argumentDef($args) &&
 462                 $this->matchChar('{', false)
 463             ) {
 464                 $func = $this->pushSpecialBlock(Type::T_FUNCTION, $s);
 465                 $func->name = $fnName;
 466                 $func->args = $args;
 467
 468                 return true;
 469             }
 470
 471             $this->seek($s);
 472
 473             if ($this->literal('@break', 6) && $this->end()) {
 474                 $this->append([Type::T_BREAK], $s);
 475
 476                 return true;
 477             }
 478
 479             $this->seek($s);
 480
 481             if ($this->literal('@continue', 9) && $this->end()) {
 482                 $this->append([Type::T_CONTINUE], $s);
 483
 484                 return true;
 485             }
 486
 487             $this->seek($s);
 488
 489             if ($this->literal('@return', 7) && ($this->valueList($retVal) || true) && $this->end()) {
 490                 $this->append([Type::T_RETURN, isset($retVal) ? $retVal : [Type::T_NULL]], $s);
 491
 492                 return true;
 493             }
 494
 495             $this->seek($s);
 496
 497             if ($this->literal('@each', 5) &&
 498                 $this->genericList($varNames, 'variable', ',', false) &&
 499                 $this->literal('in', 2) &&
 500                 $this->valueList($list) &&
 501                 $this->matchChar('{', false)
 502             ) {
 503                 $each = $this->pushSpecialBlock(Type::T_EACH, $s);
 504
 505                 foreach ($varNames[2] as $varName) {
 506                     $each->vars[] = $varName[1];
 507                 }
 508
 509                 $each->list = $list;
 510
 511                 return true;
 512             }
 513
 514             $this->seek($s);
 515
 516             if ($this->literal('@while', 6) &&
 517                 $this->expression($cond) &&
 518                 $this->matchChar('{', false)
 519             ) {
 520                 $while = $this->pushSpecialBlock(Type::T_WHILE, $s);
 521                 $while->cond = $cond;
 522
 523                 return true;
 524             }
 525
 526             $this->seek($s);
 527
 528             if ($this->literal('@for', 4) &&
 529                 $this->variable($varName) &&
 530                 $this->literal('from', 4) &&
 531                 $this->expression($start) &&
 532                 ($this->literal('through', 7) ||
 533                     ($forUntil = true && $this->literal('to', 2))) &&
 534                 $this->expression($end) &&
 535                 $this->matchChar('{', false)
 536             ) {
 537                 $for = $this->pushSpecialBlock(Type::T_FOR, $s);
 538                 $for->var   = $varName[1];
 539                 $for->start = $start;
 540                 $for->end   = $end;
 541                 $for->until = isset($forUntil);
 542
 543                 return true;
 544             }
 545
 546             $this->seek($s);
 547
 548             if ($this->literal('@if', 3) && $this->valueList($cond) && $this->matchChar('{', false)) {
 549                 $if = $this->pushSpecialBlock(Type::T_IF, $s);
 550                 while ($cond[0] === Type::T_LIST
 551                     && !empty($cond['enclosing'])
 552                     && $cond['enclosing'] === 'parent'
 553                     && count($cond[2]) == 1) {
 554                     $cond = reset($cond[2]);
 555                 }
 556                 $if->cond  = $cond;
 557                 $if->cases = [];
 558
 559                 return true;
 560             }
 561
 562             $this->seek($s);
 563
 564             if ($this->literal('@debug', 6) &&
 565                 $this->valueList($value) &&
 566                 $this->end()
 567             ) {
 568                 $this->append([Type::T_DEBUG, $value], $s);
 569
 570                 return true;
 571             }
 572
 573             $this->seek($s);
 574
 575             if ($this->literal('@warn', 5) &&
 576                 $this->valueList($value) &&
 577                 $this->end()
 578             ) {
 579                 $this->append([Type::T_WARN, $value], $s);
 580
 581                 return true;
 582             }
 583
 584             $this->seek($s);
 585
 586             if ($this->literal('@error', 6) &&
 587                 $this->valueList($value) &&
 588                 $this->end()
 589             ) {
 590                 $this->append([Type::T_ERROR, $value], $s);
 591
 592                 return true;
 593             }
 594
 595             $this->seek($s);
 596
 597             #if ($this->literal('@content', 8))
 598
 599             if ($this->literal('@content', 8) &&
 600                 ($this->end() ||
 601                     $this->matchChar('(') &&
 602                         $this->argValues($argContent) &&
 603                         $this->matchChar(')') &&
 604                     $this->end())) {
 605                 $this->append([Type::T_MIXIN_CONTENT, isset($argContent) ? $argContent : null], $s);
 606
 607                 return true;
 608             }
 609
 610             $this->seek($s);
 611
 612             $last = $this->last();
 613
 614             if (isset($last) && $last[0] === Type::T_IF) {
 615                 list(, $if) = $last;
 616
 617                 if ($this->literal('@else', 5)) {
 618                     if ($this->matchChar('{', false)) {
 619                         $else = $this->pushSpecialBlock(Type::T_ELSE, $s);
 620                     } elseif ($this->literal('if', 2) && $this->valueList($cond) && $this->matchChar('{', false)) {
 621                         $else = $this->pushSpecialBlock(Type::T_ELSEIF, $s);
 622                         $else->cond = $cond;
 623                     }
 624
 625                     if (isset($else)) {
 626                         $else->dontAppend = true;
 627                         $if->cases[] = $else;
 628
 629                         return true;
 630                     }
 631                 }
 632
 633                 $this->seek($s);
 634             }
 635
 636             // only retain the first @charset directive encountered
 637             if ($this->literal('@charset', 8) &&
 638                 $this->valueList($charset) &&
 639                 $this->end()
 640             ) {
 641                 if (! isset($this->charset)) {
 642                     $statement = [Type::T_CHARSET, $charset];
 643
 644                     list($line, $column) = $this->getSourcePosition($s);
 645
 646                     $statement[static::SOURCE_LINE]   = $line;
 647                     $statement[static::SOURCE_COLUMN] = $column;
 648                     $statement[static::SOURCE_INDEX]  = $this->sourceIndex;
 649
 650                     $this->charset = $statement;
 651                 }
 652
 653                 return true;
 654             }
 655
 656             $this->seek($s);
 657
 658             if ($this->literal('@supports', 9) &&
 659                 ($t1=$this->supportsQuery($supportQuery)) &&
 660                 ($t2=$this->matchChar('{', false))
 661             ) {
 662                 $directive = $this->pushSpecialBlock(Type::T_DIRECTIVE, $s);
 663                 $directive->name  = 'supports';
 664                 $directive->value = $supportQuery;
 665
 666                 return true;
 667             }
 668
 669             $this->seek($s);
 670
 671             // doesn't match built in directive, do generic one
 672             if ($this->matchChar('@', false) &&
 673                 $this->keyword($dirName) &&
 674                 ($this->variable($dirValue) || $this->openString('{', $dirValue) || true) &&
 675                 $this->matchChar('{', false)
 676             ) {
 677                 if ($dirName === 'media') {
 678                     $directive = $this->pushSpecialBlock(Type::T_MEDIA, $s);
 679                 } else {
 680                     $directive = $this->pushSpecialBlock(Type::T_DIRECTIVE, $s);
 681                     $directive->name = $dirName;
 682                 }
 683
 684                 if (isset($dirValue)) {
 685                     $directive->value = $dirValue;
 686                 }
 687
 688                 return true;
 689             }
 690
 691             $this->seek($s);
 692
 693             // maybe it's a generic blockless directive
 694             if ($this->matchChar('@', false) &&
 695                 $this->keyword($dirName) &&
 696                 $this->valueList($dirValue) &&
 697                 $this->end()
 698             ) {
 699                 $this->append([Type::T_DIRECTIVE, [$dirName, $dirValue]], $s);
 700
 701                 return true;
 702             }
 703
 704             $this->seek($s);
 705
 706             return false;
 707         }
 708
 709         // property shortcut
 710         // captures most properties before having to parse a selector
 711         if ($this->keyword($name, false) &&
 712             $this->literal(': ', 2) &&
 713             $this->valueList($value) &&
 714             $this->end()
 715         ) {
 716             $name = [Type::T_STRING, '', [$name]];
 717             $this->append([Type::T_ASSIGN, $name, $value], $s);
 718
 719             return true;
 720         }
 721
 722         $this->seek($s);
 723
 724         // variable assigns
 725         if ($this->variable($name) &&
 726             $this->matchChar(':') &&
 727             $this->valueList($value) &&
 728             $this->end()
 729         ) {
 730             // check for '!flag'
 731             $assignmentFlags = $this->stripAssignmentFlags($value);
 732             $this->append([Type::T_ASSIGN, $name, $value, $assignmentFlags], $s);
 733
 734             return true;
 735         }
 736
 737         $this->seek($s);
 738
 739         // misc
 740         if ($this->literal('-->', 3)) {
 741             return true;
 742         }
 743
 744         // opening css block
 745         if ($this->selectors($selectors) && $this->matchChar('{', false)) {
 746             $this->pushBlock($selectors, $s);
 747
 748             if ($this->eatWhiteDefault) {
 749                 $this->whitespace();
 750                 $this->append(null); // collect comments at the beginning if needed
 751             }
 752
 753             return true;
 754         }
 755
 756         $this->seek($s);
 757
 758         // property assign, or nested assign
 759         if ($this->propertyName($name) && $this->matchChar(':')) {
 760             $foundSomething = false;
 761
 762             if ($this->valueList($value)) {
 763                 if (empty($this->env->parent)) {
 764                     $this->throwParseError('expected "{"');
 765                 }
 766
 767                 $this->append([Type::T_ASSIGN, $name, $value], $s);
 768                 $foundSomething = true;
 769             }
 770
 771             if ($this->matchChar('{', false)) {
 772                 $propBlock = $this->pushSpecialBlock(Type::T_NESTED_PROPERTY, $s);
 773                 $propBlock->prefix = $name;
 774                 $propBlock->hasValue = $foundSomething;
 775
 776                 $foundSomething = true;
 777             } elseif ($foundSomething) {
 778                 $foundSomething = $this->end();
 779             }
 780
 781             if ($foundSomething) {
 782                 return true;
 783             }
 784         }
 785
 786         $this->seek($s);
 787
 788         // closing a block
 789         if ($this->matchChar('}', false)) {
 790             $block = $this->popBlock();
 791
 792             if (! isset($block->type) || $block->type !== Type::T_IF) {
 793                 if ($this->env->parent) {
 794                     $this->append(null); // collect comments before next statement if needed
 795                 }
 796             }
 797
 798             if (isset($block->type) && $block->type === Type::T_INCLUDE) {
 799                 $include = $block->child;
 800                 unset($block->child);
 801                 $include[3] = $block;
 802                 $this->append($include, $s);
 803             } elseif (empty($block->dontAppend)) {
 804                 $type = isset($block->type) ? $block->type : Type::T_BLOCK;
 805                 $this->append([$type, $block], $s);
 806             }
 807
 808             // collect comments just after the block closing if needed
 809             if ($this->eatWhiteDefault) {
 810                 $this->whitespace();
 811
 812                 if ($this->env->comments) {
 813                     $this->append(null);
 814                 }
 815             }
 816
 817             return true;
 818         }
 819
 820         // extra stuff
 821         if ($this->matchChar(';') ||
 822             $this->literal('<!--', 4)
 823         ) {
 824             return true;
 825         }
 826
 827         return false;
 828     }
 829
 830     /**
 831      * Push block onto parse tree
 832      *
 833      * @param array   $selectors
 834      * @param integer $pos
 835      *
 836      * @return \ScssPhp\ScssPhp\Block
 837      */
 838     protected function pushBlock($selectors, $pos = 0)
 839     {
 840         list($line, $column) = $this->getSourcePosition($pos);
 841
 842         $b = new Block;
 843         $b->sourceName   = $this->sourceName;
 844         $b->sourceLine   = $line;
 845         $b->sourceColumn = $column;
 846         $b->sourceIndex  = $this->sourceIndex;
 847         $b->selectors    = $selectors;
 848         $b->comments     = [];
 849         $b->parent       = $this->env;
 850
 851         if (! $this->env) {
 852             $b->children = [];
 853         } elseif (empty($this->env->children)) {
 854             $this->env->children = $this->env->comments;
 855             $b->children = [];
 856             $this->env->comments = [];
 857         } else {
 858             $b->children = $this->env->comments;
 859             $this->env->comments = [];
 860         }
 861
 862         $this->env = $b;
 863
 864         // collect comments at the beginning of a block if needed
 865         if ($this->eatWhiteDefault) {
 866             $this->whitespace();
 867
 868             if ($this->env->comments) {
 869                 $this->append(null);
 870             }
 871         }
 872
 873         return $b;
 874     }
 875
 876     /**
 877      * Push special (named) block onto parse tree
 878      *
 879      * @param string  $type
 880      * @param integer $pos
 881      *
 882      * @return \ScssPhp\ScssPhp\Block
 883      */
 884     protected function pushSpecialBlock($type, $pos)
 885     {
 886         $block = $this->pushBlock(null, $pos);
 887         $block->type = $type;
 888
 889         return $block;
 890     }
 891
 892     /**
 893      * Pop scope and return last block
 894      *
 895      * @return \ScssPhp\ScssPhp\Block
 896      *
 897      * @throws \Exception
 898      */
 899     protected function popBlock()
 900     {
 901
 902         // collect comments ending just before of a block closing
 903         if ($this->env->comments) {
 904             $this->append(null);
 905         }
 906
 907         // pop the block
 908         $block = $this->env;
 909
 910         if (empty($block->parent)) {
 911             $this->throwParseError('unexpected }');
 912         }
 913
 914         if ($block->type == Type::T_AT_ROOT) {
 915             // keeps the parent in case of self selector &
 916             $block->selfParent = $block->parent;
 917         }
 918
 919         $this->env = $block->parent;
 920
 921         unset($block->parent);
 922
 923         return $block;
 924     }
 925
 926     /**
 927      * Peek input stream
 928      *
 929      * @param string  $regex
 930      * @param array   $out
 931      * @param integer $from
 932      *
 933      * @return integer
 934      */
 935     protected function peek($regex, &$out, $from = null)
 936     {
 937         if (! isset($from)) {
 938             $from = $this->count;
 939         }
 940
 941         $r = '/' . $regex . '/' . $this->patternModifiers;
 942         $result = preg_match($r, $this->buffer, $out, null, $from);
 943
 944         return $result;
 945     }
 946
 947     /**
 948      * Seek to position in input stream (or return current position in input stream)
 949      *
 950      * @param integer $where
 951      */
 952     protected function seek($where)
 953     {
 954         $this->count = $where;
 955     }
 956
 957     /**
 958      * Match string looking for either ending delim, escape, or string interpolation
 959      *
 960      * {@internal This is a workaround for preg_match's 250K string match limit. }}
 961      *
 962      * @param array  $m     Matches (passed by reference)
 963      * @param string $delim Delimeter
 964      *
 965      * @return boolean True if match; false otherwise
 966      */
 967     protected function matchString(&$m, $delim)
 968     {
 969         $token = null;
 970
 971         $end = strlen($this->buffer);
 972
 973         // look for either ending delim, escape, or string interpolation
 974         foreach (['#{', '\\', $delim] as $lookahead) {
 975             $pos = strpos($this->buffer, $lookahead, $this->count);
 976
 977             if ($pos !== false && $pos < $end) {
 978                 $end = $pos;
 979                 $token = $lookahead;
 980             }
 981         }
 982
 983         if (! isset($token)) {
 984             return false;
 985         }
 986
 987         $match = substr($this->buffer, $this->count, $end - $this->count);
 988         $m = [
 989             $match . $token,
 990             $match,
 991             $token
 992         ];
 993         $this->count = $end + strlen($token);
 994
 995         return true;
 996     }
 997
 998     /**
 999      * Try to match something on head of buffer
1000      *
1001      * @param string  $regex
1002      * @param array   $out
1003      * @param boolean $eatWhitespace
1004      *
1005      * @return boolean
1006      */
1007     protected function match($regex, &$out, $eatWhitespace = null)
1008     {
1009         $r = '/' . $regex . '/' . $this->patternModifiers;
1010
1011         if (! preg_match($r, $this->buffer, $out, null, $this->count)) {
1012             return false;
1013         }
1014
1015         $this->count += strlen($out[0]);
1016
1017         if (! isset($eatWhitespace)) {
1018             $eatWhitespace = $this->eatWhiteDefault;
1019         }
1020
1021         if ($eatWhitespace) {
1022             $this->whitespace();
1023         }
1024
1025         return true;
1026     }
1027
1028     /**
1029      * Match a single string
1030      *
1031      * @param string  $char
1032      * @param boolean $eatWhitespace
1033      *
1034      * @return boolean
1035      */
1036     protected function matchChar($char, $eatWhitespace = null)
1037     {
1038         if (! isset($this->buffer[$this->count]) || $this->buffer[$this->count] !== $char) {
1039             return false;
1040         }
1041
1042         $this->count++;
1043
1044         if (! isset($eatWhitespace)) {
1045             $eatWhitespace = $this->eatWhiteDefault;
1046         }
1047
1048         if ($eatWhitespace) {
1049             $this->whitespace();
1050         }
1051
1052         return true;
1053     }
1054
1055     /**
1056      * Match literal string
1057      *
1058      * @param string  $what
1059      * @param integer $len
1060      * @param boolean $eatWhitespace
1061      *
1062      * @return boolean
1063      */
1064     protected function literal($what, $len, $eatWhitespace = null)
1065     {
1066         if (strcasecmp(substr($this->buffer, $this->count, $len), $what) !== 0) {
1067             return false;
1068         }
1069
1070         $this->count += $len;
1071
1072         if (! isset($eatWhitespace)) {
1073             $eatWhitespace = $this->eatWhiteDefault;
1074         }
1075
1076         if ($eatWhitespace) {
1077             $this->whitespace();
1078         }
1079
1080         return true;
1081     }
1082
1083     /**
1084      * Match some whitespace
1085      *
1086      * @return boolean
1087      */
1088     protected function whitespace()
1089     {
1090         $gotWhite = false;
1091
1092         while (preg_match(static::$whitePattern, $this->buffer, $m, null, $this->count)) {
1093             if (isset($m[1]) && empty($this->commentsSeen[$this->count])) {
1094                 // comment that are kept in the output CSS
1095                 $comment = [];
1096                 $startCommentCount = $this->count;
1097                 $endCommentCount = $this->count + strlen($m[1]);
1098
1099                 // find interpolations in comment
1100                 $p = strpos($this->buffer, '#{', $this->count);
1101
1102                 while ($p !== false && $p < $endCommentCount) {
1103                     $c           = substr($this->buffer, $this->count, $p - $this->count);
1104                     $comment[]   = $c;
1105                     $this->count = $p;
1106                     $out         = null;
1107
1108                     if ($this->interpolation($out)) {
1109                         // keep right spaces in the following string part
1110                         if ($out[3]) {
1111                             while ($this->buffer[$this->count-1] !== '}') {
1112                                 $this->count--;
1113                             }
1114
1115                             $out[3] = '';
1116                         }
1117
1118                         $comment[] = [Type::T_COMMENT, substr($this->buffer, $p, $this->count - $p), $out];
1119                     } else {
1120                         $comment[] = substr($this->buffer, $this->count, 2);
1121
1122                         $this->count += 2;
1123                     }
1124
1125                     $p = strpos($this->buffer, '#{', $this->count);
1126                 }
1127
1128                 // remaining part
1129                 $c = substr($this->buffer, $this->count, $endCommentCount - $this->count);
1130
1131                 if (! $comment) {
1132                     // single part static comment
1133                     $this->appendComment([Type::T_COMMENT, $c]);
1134                 } else {
1135                     $comment[] = $c;
1136                     $staticComment = substr($this->buffer, $startCommentCount, $endCommentCount - $startCommentCount);
1137                     $this->appendComment([Type::T_COMMENT, $staticComment, [Type::T_STRING, '', $comment]]);
1138                 }
1139
1140                 $this->commentsSeen[$startCommentCount] = true;
1141                 $this->count = $endCommentCount;
1142             } else {
1143                 // comment that are ignored and not kept in the output css
1144                 $this->count += strlen($m[0]);
1145             }
1146
1147             $gotWhite = true;
1148         }
1149
1150         return $gotWhite;
1151     }
1152
1153     /**
1154      * Append comment to current block
1155      *
1156      * @param array $comment
1157      */
1158     protected function appendComment($comment)
1159     {
1160         if (! $this->discardComments) {
1161             if ($comment[0] === Type::T_COMMENT) {
1162                 if (is_string($comment[1])) {
1163                     $comment[1] = substr(preg_replace(['/^\s+/m', '/^(.)/m'], ['', ' \1'], $comment[1]), 1);
1164                 }
1165                 if (isset($comment[2]) and is_array($comment[2]) and $comment[2][0] === Type::T_STRING) {
1166                     foreach ($comment[2][2] as $k => $v) {
1167                         if (is_string($v)) {
1168                             $p = strpos($v, "\n");
1169                             if ($p !== false) {
1170                                 $comment[2][2][$k] = substr($v, 0, $p + 1)
1171                                     . preg_replace(['/^\s+/m', '/^(.)/m'], ['', ' \1'], substr($v, $p+1));
1172                             }
1173                         }
1174                     }
1175                 }
1176             }
1177
1178             $this->env->comments[] = $comment;
1179         }
1180     }
1181
1182     /**
1183      * Append statement to current block
1184      *
1185      * @param array   $statement
1186      * @param integer $pos
1187      */
1188     protected function append($statement, $pos = null)
1189     {
1190         if (! is_null($statement)) {
1191             if (! is_null($pos)) {
1192                 list($line, $column) = $this->getSourcePosition($pos);
1193
1194                 $statement[static::SOURCE_LINE]   = $line;
1195                 $statement[static::SOURCE_COLUMN] = $column;
1196                 $statement[static::SOURCE_INDEX]  = $this->sourceIndex;
1197             }
1198
1199             $this->env->children[] = $statement;
1200         }
1201
1202         $comments = $this->env->comments;
1203
1204         if ($comments) {
1205             $this->env->children = array_merge($this->env->children, $comments);
1206             $this->env->comments = [];
1207         }
1208     }
1209
1210     /**
1211      * Returns last child was appended
1212      *
1213      * @return array|null
1214      */
1215     protected function last()
1216     {
1217         $i = count($this->env->children) - 1;
1218
1219         if (isset($this->env->children[$i])) {
1220             return $this->env->children[$i];
1221         }
1222     }
1223
1224     /**
1225      * Parse media query list
1226      *
1227      * @param array $out
1228      *
1229      * @return boolean
1230      */
1231     protected function mediaQueryList(&$out)
1232     {
1233         return $this->genericList($out, 'mediaQuery', ',', false);
1234     }
1235
1236     /**
1237      * Parse media query
1238      *
1239      * @param array $out
1240      *
1241      * @return boolean
1242      */
1243     protected function mediaQuery(&$out)
1244     {
1245         $expressions = null;
1246         $parts = [];
1247
1248         if (($this->literal('only', 4) && ($only = true) || $this->literal('not', 3) && ($not = true) || true) &&
1249             $this->mixedKeyword($mediaType)
1250         ) {
1251             $prop = [Type::T_MEDIA_TYPE];
1252
1253             if (isset($only)) {
1254                 $prop[] = [Type::T_KEYWORD, 'only'];
1255             }
1256
1257             if (isset($not)) {
1258                 $prop[] = [Type::T_KEYWORD, 'not'];
1259             }
1260
1261             $media = [Type::T_LIST, '', []];
1262
1263             foreach ((array) $mediaType as $type) {
1264                 if (is_array($type)) {
1265                     $media[2][] = $type;
1266                 } else {
1267                     $media[2][] = [Type::T_KEYWORD, $type];
1268                 }
1269             }
1270
1271             $prop[]  = $media;
1272             $parts[] = $prop;
1273         }
1274
1275         if (empty($parts) || $this->literal('and', 3)) {
1276             $this->genericList($expressions, 'mediaExpression', 'and', false);
1277
1278             if (is_array($expressions)) {
1279                 $parts = array_merge($parts, $expressions[2]);
1280             }
1281         }
1282
1283         $out = $parts;
1284
1285         return true;
1286     }
1287
1288     /**
1289      * Parse supports query
1290      *
1291      * @param array $out
1292      *
1293      * @return boolean
1294      */
1295     protected function supportsQuery(&$out)
1296     {
1297         $expressions = null;
1298         $parts = [];
1299
1300         $s = $this->count;
1301
1302         $not = false;
1303
1304         if (($this->literal('not', 3) && ($not = true) || true) &&
1305             $this->matchChar('(') &&
1306             ($this->expression($property)) &&
1307             $this->literal(': ', 2) &&
1308             $this->valueList($value) &&
1309             $this->matchChar(')')
1310          ) {
1311             $support = [Type::T_STRING, '', [[Type::T_KEYWORD, ($not ? 'not ' : '') . '(']]];
1312             $support[2][] = $property;
1313             $support[2][] = [Type::T_KEYWORD, ': '];
1314             $support[2][] = $value;
1315             $support[2][] = [Type::T_KEYWORD, ')'];
1316
1317             $parts[] = $support;
1318             $s = $this->count;
1319         } else {
1320             $this->seek($s);
1321         }
1322
1323         if ($this->matchChar('(') &&
1324             $this->supportsQuery($subQuery) &&
1325             $this->matchChar(')')
1326         ) {
1327             $parts[] = [Type::T_STRING, '', [[Type::T_KEYWORD, '('], $subQuery, [Type::T_KEYWORD, ')']]];
1328             $s = $this->count;
1329         } else {
1330             $this->seek($s);
1331         }
1332
1333         if ($this->literal('not', 3) &&
1334             $this->supportsQuery($subQuery)
1335         ) {
1336             $parts[] = [Type::T_STRING, '', [[Type::T_KEYWORD, 'not '], $subQuery]];
1337             $s = $this->count;
1338         } else {
1339             $this->seek($s);
1340         }
1341
1342         if ($this->literal('selector(', 9) &&
1343             $this->selector($selector) &&
1344             $this->matchChar(')')
1345         ) {
1346             $support = [Type::T_STRING, '', [[Type::T_KEYWORD, 'selector(']]];
1347
1348             $selectorList = [Type::T_LIST, '', []];
1349
1350             foreach ($selector as $sc) {
1351                 $compound = [Type::T_STRING, '', []];
1352
1353                 foreach ($sc as $scp) {
1354                     if (is_array($scp)) {
1355                         $compound[2][] = $scp;
1356                     } else {
1357                         $compound[2][] = [Type::T_KEYWORD, $scp];
1358                     }
1359                 }
1360
1361                 $selectorList[2][] = $compound;
1362             }
1363             $support[2][] = $selectorList;
1364             $support[2][] = [Type::T_KEYWORD, ')'];
1365             $parts[] = $support;
1366             $s = $this->count;
1367         } else {
1368             $this->seek($s);
1369         }
1370
1371         if ($this->variable($var) or $this->interpolation($var)) {
1372             $parts[] = $var;
1373             $s = $this->count;
1374         } else {
1375             $this->seek($s);
1376         }
1377
1378         if ($this->literal('and', 3) &&
1379             $this->genericList($expressions, 'supportsQuery', ' and', false)) {
1380             array_unshift($expressions[2], [Type::T_STRING, '', $parts]);
1381
1382             $parts = [$expressions];
1383             $s = $this->count;
1384         } else {
1385             $this->seek($s);
1386         }
1387
1388         if ($this->literal('or', 2) &&
1389             $this->genericList($expressions, 'supportsQuery', ' or', false)) {
1390             array_unshift($expressions[2], [Type::T_STRING, '', $parts]);
1391
1392             $parts = [$expressions];
1393             $s = $this->count;
1394         } else {
1395             $this->seek($s);
1396         }
1397
1398         if (count($parts)) {
1399             if ($this->eatWhiteDefault) {
1400                 $this->whitespace();
1401             }
1402
1403             $out = [Type::T_STRING, '', $parts];
1404
1405             return true;
1406         }
1407
1408         return false;
1409     }
1410
1411
1412     /**
1413      * Parse media expression
1414      *
1415      * @param array $out
1416      *
1417      * @return boolean
1418      */
1419     protected function mediaExpression(&$out)
1420     {
1421         $s = $this->count;
1422         $value = null;
1423
1424         if ($this->matchChar('(') &&
1425             $this->expression($feature) &&
1426             ($this->matchChar(':') && $this->expression($value) || true) &&
1427             $this->matchChar(')')
1428         ) {
1429             $out = [Type::T_MEDIA_EXPRESSION, $feature];
1430
1431             if ($value) {
1432                 $out[] = $value;
1433             }
1434
1435             return true;
1436         }
1437
1438         $this->seek($s);
1439
1440         return false;
1441     }
1442
1443     /**
1444      * Parse argument values
1445      *
1446      * @param array $out
1447      *
1448      * @return boolean
1449      */
1450     protected function argValues(&$out)
1451     {
1452         if ($this->genericList($list, 'argValue', ',', false)) {
1453             $out = $list[2];
1454
1455             return true;
1456         }
1457
1458         return false;
1459     }
1460
1461     /**
1462      * Parse argument value
1463      *
1464      * @param array $out
1465      *
1466      * @return boolean
1467      */
1468     protected function argValue(&$out)
1469     {
1470         $s = $this->count;
1471
1472         $keyword = null;
1473
1474         if (! $this->variable($keyword) || ! $this->matchChar(':')) {
1475             $this->seek($s);
1476
1477             $keyword = null;
1478         }
1479
1480         if ($this->genericList($value, 'expression')) {
1481             $out = [$keyword, $value, false];
1482             $s = $this->count;
1483
1484             if ($this->literal('...', 3)) {
1485                 $out[2] = true;
1486             } else {
1487                 $this->seek($s);
1488             }
1489
1490             return true;
1491         }
1492
1493         return false;
1494     }
1495
1496     /**
1497      * Parse comma separated value list
1498      *
1499      * @param array $out
1500      *
1501      * @return boolean
1502      */
1503     protected function valueList(&$out)
1504     {
1505         $discardComments = $this->discardComments;
1506         $this->discardComments = true;
1507         $res = $this->genericList($out, 'spaceList', ',');
1508         $this->discardComments = $discardComments;
1509
1510         return $res;
1511     }
1512
1513     /**
1514      * Parse space separated value list
1515      *
1516      * @param array $out
1517      *
1518      * @return boolean
1519      */
1520     protected function spaceList(&$out)
1521     {
1522         return $this->genericList($out, 'expression');
1523     }
1524
1525     /**
1526      * Parse generic list
1527      *
1528      * @param array    $out
1529      * @param callable $parseItem
1530      * @param string   $delim
1531      * @param boolean  $flatten
1532      *
1533      * @return boolean
1534      */
1535     protected function genericList(&$out, $parseItem, $delim = '', $flatten = true)
1536     {
1537         $s     = $this->count;
1538         $items = [];
1539         $value = null;
1540
1541         while ($this->$parseItem($value)) {
1542             $trailing_delim = false;
1543             $items[] = $value;
1544
1545             if ($delim) {
1546                 if (! $this->literal($delim, strlen($delim))) {
1547                     break;
1548                 }
1549                 $trailing_delim = true;
1550             }
1551         }
1552
1553         if (! $items) {
1554             $this->seek($s);
1555
1556             return false;
1557         }
1558
1559         if ($trailing_delim) {
1560             $items[] = [Type::T_NULL];
1561         }
1562         if ($flatten && count($items) === 1) {
1563             $out = $items[0];
1564         } else {
1565             $out = [Type::T_LIST, $delim, $items];
1566         }
1567
1568         return true;
1569     }
1570
1571     /**
1572      * Parse expression
1573      *
1574      * @param array $out
1575      * @param bool $listOnly
1576      * @param bool $lookForExp
1577      *
1578      * @return boolean
1579      */
1580     protected function expression(&$out, $listOnly = false, $lookForExp = true)
1581     {
1582         $s = $this->count;
1583         $discard = $this->discardComments;
1584         $this->discardComments = true;
1585         $allowedTypes = ($listOnly ? [Type::T_LIST] : [Type::T_LIST, Type::T_MAP]);
1586
1587         if ($this->matchChar('(')) {
1588             if ($this->enclosedExpression($lhs, $s, ")", $allowedTypes)) {
1589                 if ($lookForExp) {
1590                     $out = $this->expHelper($lhs, 0);
1591                 } else {
1592                     $out = $lhs;
1593                 }
1594
1595                 $this->discardComments = $discard;
1596
1597                 return true;
1598             }
1599
1600             $this->seek($s);
1601         }
1602
1603         if (in_array(Type::T_LIST, $allowedTypes) && $this->matchChar('[')) {
1604             if ($this->enclosedExpression($lhs, $s, "]", [Type::T_LIST])) {
1605                 if ($lookForExp) {
1606                     $out = $this->expHelper($lhs, 0);
1607                 } else {
1608                     $out = $lhs;
1609                 }
1610                 $this->discardComments = $discard;
1611
1612                 return true;
1613             }
1614
1615             $this->seek($s);
1616         }
1617
1618         if (!$listOnly && $this->value($lhs)) {
1619             if ($lookForExp) {
1620                 $out = $this->expHelper($lhs, 0);
1621             } else {
1622                 $out = $lhs;
1623             }
1624
1625             $this->discardComments = $discard;
1626
1627             return true;
1628         }
1629
1630         $this->discardComments = $discard;
1631         return false;
1632     }
1633
1634     /**
1635      * Parse expression specifically checking for lists in parenthesis or brackets
1636      *
1637      * @param array   $out
1638      * @param integer $s
1639      * @param string  $closingParen
1640      * @param array   $allowedTypes
1641      *
1642      * @return boolean
1643      */
1644     protected function enclosedExpression(&$out, $s, $closingParen = ")", $allowedTypes = [Type::T_LIST, Type::T_MAP])
1645     {
1646         if ($this->matchChar($closingParen) && in_array(Type::T_LIST, $allowedTypes)) {
1647             $out = [Type::T_LIST, '', []];
1648             switch ($closingParen) {
1649                 case ")":
1650                     $out['enclosing'] = 'parent'; // parenthesis list
1651                     break;
1652                 case "]":
1653                     $out['enclosing'] = 'bracket'; // bracketed list
1654                     break;
1655             }
1656             return true;
1657         }
1658
1659         if ($this->valueList($out) && $this->matchChar($closingParen)
1660             && in_array($out[0], [Type::T_LIST, Type::T_KEYWORD])
1661             && in_array(Type::T_LIST, $allowedTypes)) {
1662             if ($out[0] !== Type::T_LIST || ! empty($out['enclosing'])) {
1663                 $out = [Type::T_LIST, '', [$out]];
1664             }
1665             switch ($closingParen) {
1666                 case ")":
1667                     $out['enclosing'] = 'parent'; // parenthesis list
1668                     break;
1669                 case "]":
1670                     $out['enclosing'] = 'bracket'; // bracketed list
1671                     break;
1672             }
1673             return true;
1674         }
1675
1676         $this->seek($s);
1677
1678         if (in_array(Type::T_MAP, $allowedTypes) && $this->map($out)) {
1679             return true;
1680         }
1681
1682         return false;
1683     }
1684
1685     /**
1686      * Parse left-hand side of subexpression
1687      *
1688      * @param array   $lhs
1689      * @param integer $minP
1690      *
1691      * @return array
1692      */
1693     protected function expHelper($lhs, $minP)
1694     {
1695         $operators = static::$operatorPattern;
1696
1697         $ss = $this->count;
1698         $whiteBefore = isset($this->buffer[$this->count - 1]) &&
1699             ctype_space($this->buffer[$this->count - 1]);
1700
1701         while ($this->match($operators, $m, false) && static::$precedence[$m[1]] >= $minP) {
1702             $whiteAfter = isset($this->buffer[$this->count]) &&
1703                 ctype_space($this->buffer[$this->count]);
1704             $varAfter = isset($this->buffer[$this->count]) &&
1705                 $this->buffer[$this->count] === '$';
1706
1707             $this->whitespace();
1708
1709             $op = $m[1];
1710
1711             // don't turn negative numbers into expressions
1712             if ($op === '-' && $whiteBefore && ! $whiteAfter && ! $varAfter) {
1713                 break;
1714             }
1715
1716             if (! $this->value($rhs) && ! $this->expression($rhs, true, false)) {
1717                 break;
1718             }
1719
1720             // peek and see if rhs belongs to next operator
1721             if ($this->peek($operators, $next) && static::$precedence[$next[1]] > static::$precedence[$op]) {
1722                 $rhs = $this->expHelper($rhs, static::$precedence[$next[1]]);
1723             }
1724
1725             $lhs = [Type::T_EXPRESSION, $op, $lhs, $rhs, $this->inParens, $whiteBefore, $whiteAfter];
1726             $ss = $this->count;
1727             $whiteBefore = isset($this->buffer[$this->count - 1]) &&
1728                 ctype_space($this->buffer[$this->count - 1]);
1729         }
1730
1731         $this->seek($ss);
1732
1733         return $lhs;
1734     }
1735
1736     /**
1737      * Parse value
1738      *
1739      * @param array $out
1740      *
1741      * @return boolean
1742      */
1743     protected function value(&$out)
1744     {
1745         if (! isset($this->buffer[$this->count])) {
1746             return false;
1747         }
1748
1749         $s = $this->count;
1750         $char = $this->buffer[$this->count];
1751
1752         if ($this->literal('url(', 4) && $this->match('data:([a-z]+)\/([a-z0-9.+-]+);base64,', $m, false)) {
1753             $len = strspn(
1754                 $this->buffer,
1755                 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwyxz0123456789+/=',
1756                 $this->count
1757             );
1758
1759             $this->count += $len;
1760
1761             if ($this->matchChar(')')) {
1762                 $content = substr($this->buffer, $s, $this->count - $s);
1763                 $out = [Type::T_KEYWORD, $content];
1764
1765                 return true;
1766             }
1767         }
1768
1769         $this->seek($s);
1770
1771         if ($this->literal('url(', 4, false) && $this->match('\s*(\/\/[^\s\)]+)\s*', $m)) {
1772             $content = 'url(' . $m[1];
1773
1774             if ($this->matchChar(')')) {
1775                 $content .= ')';
1776                 $out = [Type::T_KEYWORD, $content];
1777
1778                 return true;
1779             }
1780         }
1781
1782         $this->seek($s);
1783
1784         // not
1785         if ($char === 'n' && $this->literal('not', 3, false)) {
1786             if ($this->whitespace() && $this->value($inner)) {
1787                 $out = [Type::T_UNARY, 'not', $inner, $this->inParens];
1788
1789                 return true;
1790             }
1791
1792             $this->seek($s);
1793
1794             if ($this->parenValue($inner)) {
1795                 $out = [Type::T_UNARY, 'not', $inner, $this->inParens];
1796
1797                 return true;
1798             }
1799
1800             $this->seek($s);
1801         }
1802
1803         // addition
1804         if ($char === '+') {
1805             $this->count++;
1806
1807             if ($this->value($inner)) {
1808                 $out = [Type::T_UNARY, '+', $inner, $this->inParens];
1809
1810                 return true;
1811             }
1812
1813             $this->count--;
1814
1815             return false;
1816         }
1817
1818         // negation
1819         if ($char === '-') {
1820             $this->count++;
1821
1822             if ($this->variable($inner) || $this->unit($inner) || $this->parenValue($inner)) {
1823                 $out = [Type::T_UNARY, '-', $inner, $this->inParens];
1824
1825                 return true;
1826             }
1827
1828             $this->count--;
1829         }
1830
1831         // paren
1832         if ($char === '(' && $this->parenValue($out)) {
1833             return true;
1834         }
1835
1836         if ($char === '#') {
1837             if ($this->interpolation($out) || $this->color($out)) {
1838                 return true;
1839             }
1840         }
1841
1842         if ($this->matchChar('&', true)) {
1843             $out = [Type::T_SELF];
1844
1845             return true;
1846         }
1847
1848         if ($char === '$' && $this->variable($out)) {
1849             return true;
1850         }
1851
1852         if ($char === 'p' && $this->progid($out)) {
1853             return true;
1854         }
1855
1856         if (($char === '"' || $char === "'") && $this->string($out)) {
1857             return true;
1858         }
1859
1860         if ($this->unit($out)) {
1861             return true;
1862         }
1863
1864         // unicode range with wildcards
1865         if ($this->literal('U+', 2) && $this->match('([0-9A-F]+\?*)(-([0-9A-F]+))?', $m, false)) {
1866             $out = [Type::T_KEYWORD, 'U+' . $m[0]];
1867
1868             return true;
1869         }
1870
1871         if ($this->keyword($keyword, false)) {
1872             if ($this->func($keyword, $out)) {
1873                 return true;
1874             }
1875
1876             $this->whitespace();
1877
1878             if ($keyword === 'null') {
1879                 $out = [Type::T_NULL];
1880             } else {
1881                 $out = [Type::T_KEYWORD, $keyword];
1882             }
1883
1884             return true;
1885         }
1886
1887         return false;
1888     }
1889
1890     /**
1891      * Parse parenthesized value
1892      *
1893      * @param array $out
1894      *
1895      * @return boolean
1896      */
1897     protected function parenValue(&$out)
1898     {
1899         $s = $this->count;
1900
1901         $inParens = $this->inParens;
1902
1903         if ($this->matchChar('(')) {
1904             if ($this->matchChar(')')) {
1905                 $out = [Type::T_LIST, '', []];
1906
1907                 return true;
1908             }
1909
1910             $this->inParens = true;
1911
1912             if ($this->expression($exp) && $this->matchChar(')')) {
1913                 $out = $exp;
1914                 $this->inParens = $inParens;
1915
1916                 return true;
1917             }
1918         }
1919
1920         $this->inParens = $inParens;
1921         $this->seek($s);
1922
1923         return false;
1924     }
1925
1926     /**
1927      * Parse "progid:"
1928      *
1929      * @param array $out
1930      *
1931      * @return boolean
1932      */
1933     protected function progid(&$out)
1934     {
1935         $s = $this->count;
1936
1937         if ($this->literal('progid:', 7, false) &&
1938             $this->openString('(', $fn) &&
1939             $this->matchChar('(')
1940         ) {
1941             $this->openString(')', $args, '(');
1942
1943             if ($this->matchChar(')')) {
1944                 $out = [Type::T_STRING, '', [
1945                     'progid:', $fn, '(', $args, ')'
1946                 ]];
1947
1948                 return true;
1949             }
1950         }
1951
1952         $this->seek($s);
1953
1954         return false;
1955     }
1956
1957     /**
1958      * Parse function call
1959      *
1960      * @param string $name
1961      * @param array  $func
1962      *
1963      * @return boolean
1964      */
1965     protected function func($name, &$func)
1966     {
1967         $s = $this->count;
1968
1969         if ($this->matchChar('(')) {
1970             if ($name === 'alpha' && $this->argumentList($args)) {
1971                 $func = [Type::T_FUNCTION, $name, [Type::T_STRING, '', $args]];
1972
1973                 return true;
1974             }
1975
1976             if ($name !== 'expression' && ! preg_match('/^(-[a-z]+-)?calc$/', $name)) {
1977                 $ss = $this->count;
1978
1979                 if ($this->argValues($args) && $this->matchChar(')')) {
1980                     $func = [Type::T_FUNCTION_CALL, $name, $args];
1981
1982                     return true;
1983                 }
1984
1985                 $this->seek($ss);
1986             }
1987
1988             if (($this->openString(')', $str, '(') || true) &&
1989                 $this->matchChar(')')
1990             ) {
1991                 $args = [];
1992
1993                 if (! empty($str)) {
1994                     $args[] = [null, [Type::T_STRING, '', [$str]]];
1995                 }
1996
1997                 $func = [Type::T_FUNCTION_CALL, $name, $args];
1998
1999                 return true;
2000             }
2001         }
2002
2003         $this->seek($s);
2004
2005         return false;
2006     }
2007
2008     /**
2009      * Parse function call argument list
2010      *
2011      * @param array $out
2012      *
2013      * @return boolean
2014      */
2015     protected function argumentList(&$out)
2016     {
2017         $s = $this->count;
2018         $this->matchChar('(');
2019
2020         $args = [];
2021
2022         while ($this->keyword($var)) {
2023             if ($this->matchChar('=') && $this->expression($exp)) {
2024                 $args[] = [Type::T_STRING, '', [$var . '=']];
2025                 $arg = $exp;
2026             } else {
2027                 break;
2028             }
2029
2030             $args[] = $arg;
2031
2032             if (! $this->matchChar(',')) {
2033                 break;
2034             }
2035
2036             $args[] = [Type::T_STRING, '', [', ']];
2037         }
2038
2039         if (! $this->matchChar(')') || ! $args) {
2040             $this->seek($s);
2041
2042             return false;
2043         }
2044
2045         $out = $args;
2046
2047         return true;
2048     }
2049
2050     /**
2051      * Parse mixin/function definition  argument list
2052      *
2053      * @param array $out
2054      *
2055      * @return boolean
2056      */
2057     protected function argumentDef(&$out)
2058     {
2059         $s = $this->count;
2060         $this->matchChar('(');
2061
2062         $args = [];
2063
2064         while ($this->variable($var)) {
2065             $arg = [$var[1], null, false];
2066
2067             $ss = $this->count;
2068
2069             if ($this->matchChar(':') && $this->genericList($defaultVal, 'expression')) {
2070                 $arg[1] = $defaultVal;
2071             } else {
2072                 $this->seek($ss);
2073             }
2074
2075             $ss = $this->count;
2076
2077             if ($this->literal('...', 3)) {
2078                 $sss = $this->count;
2079
2080                 if (! $this->matchChar(')')) {
2081                     $this->throwParseError('... has to be after the final argument');
2082                 }
2083
2084                 $arg[2] = true;
2085                 $this->seek($sss);
2086             } else {
2087                 $this->seek($ss);
2088             }
2089
2090             $args[] = $arg;
2091
2092             if (! $this->matchChar(',')) {
2093                 break;
2094             }
2095         }
2096
2097         if (! $this->matchChar(')')) {
2098             $this->seek($s);
2099
2100             return false;
2101         }
2102
2103         $out = $args;
2104
2105         return true;
2106     }
2107
2108     /**
2109      * Parse map
2110      *
2111      * @param array $out
2112      *
2113      * @return boolean
2114      */
2115     protected function map(&$out)
2116     {
2117         $s = $this->count;
2118
2119         if (! $this->matchChar('(')) {
2120             return false;
2121         }
2122
2123         $keys = [];
2124         $values = [];
2125
2126         while ($this->genericList($key, 'expression') && $this->matchChar(':') &&
2127             $this->genericList($value, 'expression')
2128         ) {
2129             $keys[] = $key;
2130             $values[] = $value;
2131
2132             if (! $this->matchChar(',')) {
2133                 break;
2134             }
2135         }
2136
2137         if (! $keys || ! $this->matchChar(')')) {
2138             $this->seek($s);
2139
2140             return false;
2141         }
2142
2143         $out = [Type::T_MAP, $keys, $values];
2144
2145         return true;
2146     }
2147
2148     /**
2149      * Parse color
2150      *
2151      * @param array $out
2152      *
2153      * @return boolean
2154      */
2155     protected function color(&$out)
2156     {
2157         $s = $this->count;
2158
2159         if ($this->match('(#([0-9a-f]+))', $m)) {
2160             if (in_array(strlen($m[2]), [3,4,6,8])) {
2161                 $out = [Type::T_KEYWORD, $m[0]];
2162                 return true;
2163             }
2164
2165             $this->seek($s);
2166             return false;
2167         }
2168
2169         return false;
2170     }
2171
2172     /**
2173      * Parse number with unit
2174      *
2175      * @param array $unit
2176      *
2177      * @return boolean
2178      */
2179     protected function unit(&$unit)
2180     {
2181         $s = $this->count;
2182
2183         if ($this->match('([0-9]*(\.)?[0-9]+)([%a-zA-Z]+)?', $m, false)) {
2184             if (strlen($this->buffer) === $this->count || ! ctype_digit($this->buffer[$this->count])) {
2185                 $this->whitespace();
2186
2187                 $unit = new Node\Number($m[1], empty($m[3]) ? '' : $m[3]);
2188
2189                 return true;
2190             }
2191
2192             $this->seek($s);
2193         }
2194
2195         return false;
2196     }
2197
2198     /**
2199      * Parse string
2200      *
2201      * @param array $out
2202      *
2203      * @return boolean
2204      */
2205     protected function string(&$out)
2206     {
2207         $s = $this->count;
2208
2209         if ($this->matchChar('"', false)) {
2210             $delim = '"';
2211         } elseif ($this->matchChar("'", false)) {
2212             $delim = "'";
2213         } else {
2214             return false;
2215         }
2216
2217         $content = [];
2218         $oldWhite = $this->eatWhiteDefault;
2219         $this->eatWhiteDefault = false;
2220         $hasInterpolation = false;
2221
2222         while ($this->matchString($m, $delim)) {
2223             if ($m[1] !== '') {
2224                 $content[] = $m[1];
2225             }
2226
2227             if ($m[2] === '#{') {
2228                 $this->count -= strlen($m[2]);
2229
2230                 if ($this->interpolation($inter, false)) {
2231                     $content[] = $inter;
2232                     $hasInterpolation = true;
2233                 } else {
2234                     $this->count += strlen($m[2]);
2235                     $content[] = '#{'; // ignore it
2236                 }
2237             } elseif ($m[2] === '\\') {
2238                 if ($this->matchChar('"', false)) {
2239                     $content[] = $m[2] . '"';
2240                 } elseif ($this->matchChar("'", false)) {
2241                     $content[] = $m[2] . "'";
2242                 } elseif ($this->literal("\\", 1, false)) {
2243                     $content[] = $m[2] . "\\";
2244                 } elseif ($this->literal("\r\n", 2, false) ||
2245                   $this->matchChar("\r", false) ||
2246                   $this->matchChar("\n", false) ||
2247                   $this->matchChar("\f", false)
2248                 ) {
2249                     // this is a continuation escaping, to be ignored
2250                 } else {
2251                     $content[] = $m[2];
2252                 }
2253             } else {
2254                 $this->count -= strlen($delim);
2255                 break; // delim
2256             }
2257         }
2258
2259         $this->eatWhiteDefault = $oldWhite;
2260
2261         if ($this->literal($delim, strlen($delim))) {
2262             if ($hasInterpolation) {
2263                 $delim = '"';
2264
2265                 foreach ($content as &$string) {
2266                     if ($string === "\\\\") {
2267                         $string = "\\";
2268                     } elseif ($string === "\\'") {
2269                         $string = "'";
2270                     } elseif ($string === '\\"') {
2271                         $string = '"';
2272                     }
2273                 }
2274             }
2275
2276             $out = [Type::T_STRING, $delim, $content];
2277
2278             return true;
2279         }
2280
2281         $this->seek($s);
2282
2283         return false;
2284     }
2285
2286     /**
2287      * Parse keyword or interpolation
2288      *
2289      * @param array   $out
2290      * @param boolean $restricted
2291      *
2292      * @return boolean
2293      */
2294     protected function mixedKeyword(&$out, $restricted = false)
2295     {
2296         $parts = [];
2297
2298         $oldWhite = $this->eatWhiteDefault;
2299         $this->eatWhiteDefault = false;
2300
2301         for (;;) {
2302             if ($restricted ? $this->restrictedKeyword($key) : $this->keyword($key)) {
2303                 $parts[] = $key;
2304                 continue;
2305             }
2306
2307             if ($this->interpolation($inter)) {
2308                 $parts[] = $inter;
2309                 continue;
2310             }
2311
2312             break;
2313         }
2314
2315         $this->eatWhiteDefault = $oldWhite;
2316
2317         if (! $parts) {
2318             return false;
2319         }
2320
2321         if ($this->eatWhiteDefault) {
2322             $this->whitespace();
2323         }
2324
2325         $out = $parts;
2326
2327         return true;
2328     }
2329
2330     /**
2331      * Parse an unbounded string stopped by $end
2332      *
2333      * @param string $end
2334      * @param array  $out
2335      * @param string $nestingOpen
2336      *
2337      * @return boolean
2338      */
2339     protected function openString($end, &$out, $nestingOpen = null)
2340     {
2341         $oldWhite = $this->eatWhiteDefault;
2342         $this->eatWhiteDefault = false;
2343
2344         $patt = '(.*?)([\'"]|#\{|' . $this->pregQuote($end) . '|' . static::$commentPattern . ')';
2345
2346         $nestingLevel = 0;
2347
2348         $content = [];
2349
2350         while ($this->match($patt, $m, false)) {
2351             if (isset($m[1]) && $m[1] !== '') {
2352                 $content[] = $m[1];
2353
2354                 if ($nestingOpen) {
2355                     $nestingLevel += substr_count($m[1], $nestingOpen);
2356                 }
2357             }
2358
2359             $tok = $m[2];
2360
2361             $this->count-= strlen($tok);
2362
2363             if ($tok === $end && ! $nestingLevel--) {
2364                 break;
2365             }
2366
2367             if (($tok === "'" || $tok === '"') && $this->string($str)) {
2368                 $content[] = $str;
2369                 continue;
2370             }
2371
2372             if ($tok === '#{' && $this->interpolation($inter)) {
2373                 $content[] = $inter;
2374                 continue;
2375             }
2376
2377             $content[] = $tok;
2378             $this->count+= strlen($tok);
2379         }
2380
2381         $this->eatWhiteDefault = $oldWhite;
2382
2383         if (! $content) {
2384             return false;
2385         }
2386
2387         // trim the end
2388         if (is_string(end($content))) {
2389             $content[count($content) - 1] = rtrim(end($content));
2390         }
2391
2392         $out = [Type::T_STRING, '', $content];
2393
2394         return true;
2395     }
2396
2397     /**
2398      * Parser interpolation
2399      *
2400      * @param string|array $out
2401      * @param boolean      $lookWhite save information about whitespace before and after
2402      *
2403      * @return boolean
2404      */
2405     protected function interpolation(&$out, $lookWhite = true)
2406     {
2407         $oldWhite = $this->eatWhiteDefault;
2408         $this->eatWhiteDefault = true;
2409
2410         $s = $this->count;
2411
2412         if ($this->literal('#{', 2) && $this->valueList($value) && $this->matchChar('}', false)) {
2413             if ($value === [Type::T_SELF]) {
2414                 $out = $value;
2415             } else {
2416                 if ($lookWhite) {
2417                     $left = ($s > 0 && preg_match('/\s/', $this->buffer[$s - 1])) ? ' ' : '';
2418                     $right = preg_match('/\s/', $this->buffer[$this->count]) ? ' ': '';
2419                 } else {
2420                     $left = $right = false;
2421                 }
2422
2423                 $out = [Type::T_INTERPOLATE, $value, $left, $right];
2424             }
2425
2426             $this->eatWhiteDefault = $oldWhite;
2427
2428             if ($this->eatWhiteDefault) {
2429                 $this->whitespace();
2430             }
2431
2432             return true;
2433         }
2434
2435         $this->seek($s);
2436
2437         $this->eatWhiteDefault = $oldWhite;
2438
2439         return false;
2440     }
2441
2442     /**
2443      * Parse property name (as an array of parts or a string)
2444      *
2445      * @param array $out
2446      *
2447      * @return boolean
2448      */
2449     protected function propertyName(&$out)
2450     {
2451         $parts = [];
2452
2453         $oldWhite = $this->eatWhiteDefault;
2454         $this->eatWhiteDefault = false;
2455
2456         for (;;) {
2457             if ($this->interpolation($inter)) {
2458                 $parts[] = $inter;
2459                 continue;
2460             }
2461
2462             if ($this->keyword($text)) {
2463                 $parts[] = $text;
2464                 continue;
2465             }
2466
2467             if (! $parts && $this->match('[:.#]', $m, false)) {
2468                 // css hacks
2469                 $parts[] = $m[0];
2470                 continue;
2471             }
2472
2473             break;
2474         }
2475
2476         $this->eatWhiteDefault = $oldWhite;
2477
2478         if (! $parts) {
2479             return false;
2480         }
2481
2482         // match comment hack
2483         if (preg_match(
2484             static::$whitePattern,
2485             $this->buffer,
2486             $m,
2487             null,
2488             $this->count
2489         )) {
2490             if (! empty($m[0])) {
2491                 $parts[] = $m[0];
2492                 $this->count += strlen($m[0]);
2493             }
2494         }
2495
2496         $this->whitespace(); // get any extra whitespace
2497
2498         $out = [Type::T_STRING, '', $parts];
2499
2500         return true;
2501     }
2502
2503     /**
2504      * Parse comma separated selector list
2505      *
2506      * @param array   $out
2507      * @param boolean $subSelector
2508      *
2509      * @return boolean
2510      */
2511     protected function selectors(&$out, $subSelector = false)
2512     {
2513         $s = $this->count;
2514         $selectors = [];
2515
2516         while ($this->selector($sel, $subSelector)) {
2517             $selectors[] = $sel;
2518
2519             if (! $this->matchChar(',', true)) {
2520                 break;
2521             }
2522
2523             while ($this->matchChar(',', true)) {
2524                 ; // ignore extra
2525             }
2526         }
2527
2528         if (! $selectors) {
2529             $this->seek($s);
2530
2531             return false;
2532         }
2533
2534         $out = $selectors;
2535
2536         return true;
2537     }
2538
2539     /**
2540      * Parse whitespace separated selector list
2541      *
2542      * @param array   $out
2543      * @param boolean $subSelector
2544      *
2545      * @return boolean
2546      */
2547     protected function selector(&$out, $subSelector = false)
2548     {
2549         $selector = [];
2550
2551         for (;;) {
2552             $s = $this->count;
2553
2554             if ($this->match('[>+~]+', $m, true)) {
2555                 if ($subSelector && is_string($subSelector) && strpos($subSelector, 'nth-') === 0 &&
2556                     $m[0] === '+' && $this->match("(\d+|n\b)", $counter)
2557                 ) {
2558                     $this->seek($s);
2559                 } else {
2560                     $selector[] = [$m[0]];
2561                     continue;
2562                 }
2563             }
2564
2565             if ($this->selectorSingle($part, $subSelector)) {
2566                 $selector[] = $part;
2567                 $this->match('\s+', $m);
2568                 continue;
2569             }
2570
2571             if ($this->match('\/[^\/]+\/', $m, true)) {
2572                 $selector[] = [$m[0]];
2573                 continue;
2574             }
2575
2576             break;
2577         }
2578
2579         if (! $selector) {
2580             return false;
2581         }
2582
2583         $out = $selector;
2584
2585         return true;
2586     }
2587
2588     /**
2589      * Parse the parts that make up a selector
2590      *
2591      * {@internal
2592      *     div[yes=no]#something.hello.world:nth-child(-2n+1)%placeholder
2593      * }}
2594      *
2595      * @param array   $out
2596      * @param boolean $subSelector
2597      *
2598      * @return boolean
2599      */
2600     protected function selectorSingle(&$out, $subSelector = false)
2601     {
2602         $oldWhite = $this->eatWhiteDefault;
2603         $this->eatWhiteDefault = false;
2604
2605         $parts = [];
2606
2607         if ($this->matchChar('*', false)) {
2608             $parts[] = '*';
2609         }
2610
2611         for (;;) {
2612             if (! isset($this->buffer[$this->count])) {
2613                 break;
2614             }
2615
2616             $s = $this->count;
2617             $char = $this->buffer[$this->count];
2618
2619             // see if we can stop early
2620             if ($char === '{' || $char === ',' || $char === ';' || $char === '}' || $char === '@') {
2621                 break;
2622             }
2623
2624             // parsing a sub selector in () stop with the closing )
2625             if ($subSelector && $char === ')') {
2626                 break;
2627             }
2628
2629             //self
2630             switch ($char) {
2631                 case '&':
2632                     $parts[] = Compiler::$selfSelector;
2633                     $this->count++;
2634                     continue 2;
2635
2636                 case '.':
2637                     $parts[] = '.';
2638                     $this->count++;
2639                     continue 2;
2640
2641                 case '|':
2642                     $parts[] = '|';
2643                     $this->count++;
2644                     continue 2;
2645             }
2646
2647             if ($char === '\\' && $this->match('\\\\\S', $m)) {
2648                 $parts[] = $m[0];
2649                 continue;
2650             }
2651
2652             if ($char === '%') {
2653                 $this->count++;
2654
2655                 if ($this->placeholder($placeholder)) {
2656                     $parts[] = '%';
2657                     $parts[] = $placeholder;
2658                     continue;
2659                 }
2660
2661                 break;
2662             }
2663
2664             if ($char === '#') {
2665                 if ($this->interpolation($inter)) {
2666                     $parts[] = $inter;
2667                     continue;
2668                 }
2669
2670                 $parts[] = '#';
2671                 $this->count++;
2672                 continue;
2673             }
2674
2675             // a pseudo selector
2676             if ($char === ':') {
2677                 if ($this->buffer[$this->count + 1] === ':') {
2678                     $this->count += 2;
2679                     $part = '::';
2680                 } else {
2681                     $this->count++;
2682                     $part = ':';
2683                 }
2684
2685                 if ($this->mixedKeyword($nameParts, true)) {
2686                     $parts[] = $part;
2687
2688                     foreach ($nameParts as $sub) {
2689                         $parts[] = $sub;
2690                     }
2691
2692                     $ss = $this->count;
2693
2694                     if ($nameParts === ['not'] || $nameParts === ['is'] ||
2695                         $nameParts === ['has'] || $nameParts === ['where'] ||
2696                         $nameParts === ['slotted'] ||
2697                         $nameParts === ['nth-child'] || $nameParts == ['nth-last-child'] ||
2698                         $nameParts === ['nth-of-type'] || $nameParts == ['nth-last-of-type']
2699                     ) {
2700                         if ($this->matchChar('(', true) &&
2701                           ($this->selectors($subs, reset($nameParts)) || true) &&
2702                           $this->matchChar(')')
2703                         ) {
2704                             $parts[] = '(';
2705
2706                             while ($sub = array_shift($subs)) {
2707                                 while ($ps = array_shift($sub)) {
2708                                     foreach ($ps as &$p) {
2709                                         $parts[] = $p;
2710                                     }
2711
2712                                     if (count($sub) && reset($sub)) {
2713                                         $parts[] = ' ';
2714                                     }
2715                                 }
2716
2717                                 if (count($subs) && reset($subs)) {
2718                                     $parts[] = ', ';
2719                                 }
2720                             }
2721
2722                             $parts[] = ')';
2723                         } else {
2724                             $this->seek($ss);
2725                         }
2726                     } else {
2727                         if ($this->matchChar('(') &&
2728                           ($this->openString(')', $str, '(') || true) &&
2729                           $this->matchChar(')')
2730                         ) {
2731                             $parts[] = '(';
2732
2733                             if (! empty($str)) {
2734                                 $parts[] = $str;
2735                             }
2736
2737                             $parts[] = ')';
2738                         } else {
2739                             $this->seek($ss);
2740                         }
2741                     }
2742
2743                     continue;
2744                 }
2745             }
2746
2747             $this->seek($s);
2748
2749             // 2n+1
2750             if ($subSelector && is_string($subSelector) && strpos($subSelector, 'nth-') === 0) {
2751                 if ($this->match("(\s*(\+\s*|\-\s*)?(\d+|n|\d+n))+", $counter)) {
2752                     $parts[] = $counter[0];
2753                     //$parts[] = str_replace(' ', '', $counter[0]);
2754                     continue;
2755                 }
2756             }
2757
2758             $this->seek($s);
2759
2760             // attribute selector
2761             if ($char === '[' &&
2762                 $this->matchChar('[') &&
2763                 ($this->openString(']', $str, '[') || true) &&
2764                 $this->matchChar(']')
2765             ) {
2766                 $parts[] = '[';
2767
2768                 if (! empty($str)) {
2769                     $parts[] = $str;
2770                 }
2771
2772                 $parts[] = ']';
2773                 continue;
2774             }
2775
2776             $this->seek($s);
2777
2778             // for keyframes
2779             if ($this->unit($unit)) {
2780                 $parts[] = $unit;
2781                 continue;
2782             }
2783
2784             if ($this->restrictedKeyword($name)) {
2785                 $parts[] = $name;
2786                 continue;
2787             }
2788
2789             break;
2790         }
2791
2792         $this->eatWhiteDefault = $oldWhite;
2793
2794         if (! $parts) {
2795             return false;
2796         }
2797
2798         $out = $parts;
2799
2800         return true;
2801     }
2802
2803     /**
2804      * Parse a variable
2805      *
2806      * @param array $out
2807      *
2808      * @return boolean
2809      */
2810     protected function variable(&$out)
2811     {
2812         $s = $this->count;
2813
2814         if ($this->matchChar('$', false) && $this->keyword($name)) {
2815             $out = [Type::T_VARIABLE, $name];
2816
2817             return true;
2818         }
2819
2820         $this->seek($s);
2821
2822         return false;
2823     }
2824
2825     /**
2826      * Parse a keyword
2827      *
2828      * @param string  $word
2829      * @param boolean $eatWhitespace
2830      *
2831      * @return boolean
2832      */
2833     protected function keyword(&$word, $eatWhitespace = null)
2834     {
2835         if ($this->match(
2836             $this->utf8
2837                 ? '(([\pL\w\x{00A0}-\x{10FFFF}_\-\*!"\']|[\\\\].)([\pL\w\x{00A0}-\x{10FFFF}\-_"\']|[\\\\].)*)'
2838                 : '(([\w_\-\*!"\']|[\\\\].)([\w\-_"\']|[\\\\].)*)',
2839             $m,
2840             $eatWhitespace
2841         )) {
2842             $word = $m[1];
2843
2844             return true;
2845         }
2846
2847         return false;
2848     }
2849
2850     /**
2851      * Parse a keyword that should not start with a number
2852      *
2853      * @param string  $word
2854      * @param boolean $eatWhitespace
2855      *
2856      * @return boolean
2857      */
2858     protected function restrictedKeyword(&$word, $eatWhitespace = null)
2859     {
2860         $s = $this->count;
2861
2862         if ($this->keyword($word, $eatWhitespace) && (ord($word[0]) > 57 || ord($word[0]) < 48)) {
2863             return true;
2864         }
2865
2866         $this->seek($s);
2867
2868         return false;
2869     }
2870
2871     /**
2872      * Parse a placeholder
2873      *
2874      * @param string|array $placeholder
2875      *
2876      * @return boolean
2877      */
2878     protected function placeholder(&$placeholder)
2879     {
2880         if ($this->match(
2881             $this->utf8
2882                 ? '([\pL\w\-_]+)'
2883                 : '([\w\-_]+)',
2884             $m
2885         )) {
2886             $placeholder = $m[1];
2887
2888             return true;
2889         }
2890
2891         if ($this->interpolation($placeholder)) {
2892             return true;
2893         }
2894
2895         return false;
2896     }
2897
2898     /**
2899      * Parse a url
2900      *
2901      * @param array $out
2902      *
2903      * @return boolean
2904      */
2905     protected function url(&$out)
2906     {
2907         if ($this->match('(url\(\s*(["\']?)([^)]+)\2\s*\))', $m)) {
2908             $out = [Type::T_STRING, '', ['url(' . $m[2] . $m[3] . $m[2] . ')']];
2909
2910             return true;
2911         }
2912
2913         return false;
2914     }
2915
2916     /**
2917      * Consume an end of statement delimiter
2918      *
2919      * @return boolean
2920      */
2921     protected function end()
2922     {
2923         if ($this->matchChar(';')) {
2924             return true;
2925         }
2926
2927         if ($this->count === strlen($this->buffer) || $this->buffer[$this->count] === '}') {
2928             // if there is end of file or a closing block next then we don't need a ;
2929             return true;
2930         }
2931
2932         return false;
2933     }
2934
2935     /**
2936      * Strip assignment flag from the list
2937      *
2938      * @param array $value
2939      *
2940      * @return array
2941      */
2942     protected function stripAssignmentFlags(&$value)
2943     {
2944         $flags = [];
2945
2946         for ($token = &$value; $token[0] === Type::T_LIST && ($s = count($token[2])); $token = &$lastNode) {
2947             $lastNode = &$token[2][$s - 1];
2948
2949             while ($lastNode[0] === Type::T_KEYWORD && in_array($lastNode[1], ['!default', '!global'])) {
2950                 array_pop($token[2]);
2951
2952                 $node     = end($token[2]);
2953                 $token    = $this->flattenList($token);
2954                 $flags[]  = $lastNode[1];
2955                 $lastNode = $node;
2956             }
2957         }
2958
2959         return $flags;
2960     }
2961
2962     /**
2963      * Strip optional flag from selector list
2964      *
2965      * @param array $selectors
2966      *
2967      * @return string
2968      */
2969     protected function stripOptionalFlag(&$selectors)
2970     {
2971         $optional = false;
2972         $selector = end($selectors);
2973         $part     = end($selector);
2974
2975         if ($part === ['!optional']) {
2976             array_pop($selectors[count($selectors) - 1]);
2977
2978             $optional = true;
2979         }
2980
2981         return $optional;
2982     }
2983
2984     /**
2985      * Turn list of length 1 into value type
2986      *
2987      * @param array $value
2988      *
2989      * @return array
2990      */
2991     protected function flattenList($value)
2992     {
2993         if ($value[0] === Type::T_LIST && count($value[2]) === 1) {
2994             return $this->flattenList($value[2][0]);
2995         }
2996
2997         return $value;
2998     }
2999
3000     /**
3001      * @deprecated
3002      *
3003      * {@internal
3004      *     advance counter to next occurrence of $what
3005      *     $until - don't include $what in advance
3006      *     $allowNewline, if string, will be used as valid char set
3007      * }}
3008      */
3009     protected function to($what, &$out, $until = false, $allowNewline = false)
3010     {
3011         if (is_string($allowNewline)) {
3012             $validChars = $allowNewline;
3013         } else {
3014             $validChars = $allowNewline ? '.' : "[^\n]";
3015         }
3016
3017         $m = null;
3018
3019         if (! $this->match('(' . $validChars . '*?)' . $this->pregQuote($what), $m, ! $until)) {
3020             return false;
3021         }
3022
3023         if ($until) {
3024             $this->count -= strlen($what); // give back $what
3025         }
3026
3027         $out = $m[1];
3028
3029         return true;
3030     }
3031
3032     /**
3033      * @deprecated
3034      */
3035     protected function show()
3036     {
3037         if ($this->peek("(.*?)(\n|$)", $m, $this->count)) {
3038             return $m[1];
3039         }
3040
3041         return '';
3042     }
3043
3044     /**
3045      * Quote regular expression
3046      *
3047      * @param string $what
3048      *
3049      * @return string
3050      */
3051     private function pregQuote($what)
3052     {
3053         return preg_quote($what, '/');
3054     }
3055
3056     /**
3057      * Extract line numbers from buffer
3058      *
3059      * @param string $buffer
3060      */
3061     private function extractLineNumbers($buffer)
3062     {
3063         $this->sourcePositions = [0 => 0];
3064         $prev = 0;
3065
3066         while (($pos = strpos($buffer, "\n", $prev)) !== false) {
3067             $this->sourcePositions[] = $pos;
3068             $prev = $pos + 1;
3069         }
3070
3071         $this->sourcePositions[] = strlen($buffer);
3072
3073         if (substr($buffer, -1) !== "\n") {
3074             $this->sourcePositions[] = strlen($buffer) + 1;
3075         }
3076     }
3077
3078     /**
3079      * Get source line number and column (given character position in the buffer)
3080      *
3081      * @param integer $pos
3082      *
3083      * @return array
3084      */
3085     private function getSourcePosition($pos)
3086     {
3087         $low = 0;
3088         $high = count($this->sourcePositions);
3089
3090         while ($low < $high) {
3091             $mid = (int) (($high + $low) / 2);
3092
3093             if ($pos < $this->sourcePositions[$mid]) {
3094                 $high = $mid - 1;
3095                 continue;
3096             }
3097
3098             if ($pos >= $this->sourcePositions[$mid + 1]) {
3099                 $low = $mid + 1;
3100                 continue;
3101             }
3102
3103             return [$mid + 1, $pos - $this->sourcePositions[$mid]];
3104         }
3105
3106         return [$low + 1, $pos - $this->sourcePositions[$low]];
3107     }
3108
3109     /**
3110      * Save internal encoding
3111      */
3112     private function saveEncoding()
3113     {
3114         if (version_compare(PHP_VERSION, '7.2.0') >= 0) {
3115             return;
3116         }
3117
3118         // deprecated in PHP 7.2
3119         $iniDirective = 'mbstring.func_overload';
3120
3121         if (extension_loaded('mbstring') && ini_get($iniDirective) & 2) {
3122             $this->encoding = mb_internal_encoding();
3123
3124             mb_internal_encoding('iso-8859-1');
3125         }
3126     }
3127
3128     /**
3129      * Restore internal encoding
3130      */
3131     private function restoreEncoding()
3132     {
3133         if (extension_loaded('mbstring') && $this->encoding) {
3134             mb_internal_encoding($this->encoding);
3135         }
3136     }
3137 }