Leafo\ScssPhp\Parser::parseSelector PHP Method

    public function parseSelector($buffer, &$out)
    {
        $this->count = 0;
        $this->env = null;
        $this->inParens = false;
        $this->eatWhiteDefault = true;
        $this->buffer = (string) $buffer;
        $this->saveEncoding();
        $selector = $this->selectors($out);
        $this->restoreEncoding();
        return $selector;
    }

 /**
  * Evaluate selectors
  *
  * @param array $selectors
  *
  * @return array
  */
 protected function evalSelectors($selectors)
 {
     $this->shouldEvaluate = false;
     $selectors = array_map(array($this, 'evalSelector'), $selectors);
     // after evaluating interpolates, we might need a second pass
     if ($this->shouldEvaluate) {
         $buffer = $this->collapseSelectors($selectors);
         $parser = new Parser(__METHOD__, false);
         if ($parser->parseSelector($buffer, $newSelectors)) {
             $selectors = array_map(array($this, 'evalSelector'), $newSelectors);
         }
     }
     return $selectors;
 }