Leafo\ScssPhp\Parser::openString PHP Method

    protected function openString($end, &$out, $nestingOpen = null)
    {
        $oldWhite = $this->eatWhiteDefault;
        $this->eatWhiteDefault = false;
        $patt = '(.*?)([\'"]|#\\{|' . $this->pregQuote($end) . '|' . static::$commentPattern . ')';
        $nestingLevel = 0;
        $content = [];
        while ($this->match($patt, $m, false)) {
            if (isset($m[1]) && $m[1] !== '') {
                $content[] = $m[1];
                if ($nestingOpen) {
                    $nestingLevel += substr_count($m[1], $nestingOpen);
                }
            }
            $tok = $m[2];
            $this->count -= strlen($tok);
            if ($tok === $end && !$nestingLevel--) {
                break;
            }
            if (($tok === "'" || $tok === '"') && $this->string($str)) {
                $content[] = $str;
                continue;
            }
            if ($tok === '#{' && $this->interpolation($inter)) {
                $content[] = $inter;
                continue;
            }
            $content[] = $tok;
            $this->count += strlen($tok);
        }
        $this->eatWhiteDefault = $oldWhite;
        if (count($content) === 0) {
            return false;
        }
        // trim the end
        if (is_string(end($content))) {
            $content[count($content) - 1] = rtrim(end($content));
        }
        $out = [Type::T_STRING, '', $content];
        return true;
    }