Sprockets\File::processDirectives PHP Method

    private function processDirectives($content)
    {
        /**
         * Recognizes :
         * ALl:
         *  NEWLINE" *=" (processed only in comment)
         * JS:
         *  "//="
         *  "#="
         */
        if (false === strpos($content, "\n *=") && false === strpos($content, '//=') && false === strpos($content, '#=')) {
            return $content;
        }
        $new_content = '';
        $lines = explode("\n", $content);
        $in_comment = false;
        for ($i = 0, $len = count($lines); $i < $len; ++$i) {
            $line = $lines[$i];
            if (substr($line, 0, 2) == '/*') {
                $in_comment = true;
                continue;
            }
            if ($in_comment && substr(trim($line), 0, 2) == '*/') {
                $in_comment = false;
                continue;
            }
            //a bit verbose, but definitely more readable ...
            $is_directive = false;
            if ($in_comment && substr(trim($line), 0, 2) == '*=') {
                $is_directive = true;
            }
            if ($this->type == 'js') {
                if (substr($line, 0, 3) == '//=') {
                    $is_directive = true;
                }
                if (substr($line, 0, 2) == '#=') {
                    $is_directive = true;
                }
            }
            if ($is_directive) {
                $directive = explode(' ', trim(substr($line, 3)));
                $function = $directive[0];
                $argument = $directive[1];
                $last = substr($argument, -1);
                while ($last == '\\' || $last == ',') {
                    //parse as many lines as needed
                    if ($last == '\\') {
                        //  remove trailing \    remove leading //
                        $argument = substr($argument, 0, -1) . trim(substr($next = trim($lines[++$i]), 2));
                    } else {
                        if ($last == ',') {
                            $next = trim($lines[++$i]);
                            $argument .= ltrim($next, '/#*=');
                        }
                    }
                    $last = substr($next, -1);
                }
                $method = pascalize($function) . 'Directive';
                if (!method_exists($this, $method)) {
                    throw new \RuntimeException('Cannot parse file ' . $this->path . ', unknow directive ' . $function);
                }
                $new_content .= call_user_func(array($this, $method), $argument) . "\n";
            } else {
                if (!$in_comment) {
                    //we can't balance comments.
                    $new_content .= $line . "\n";
                }
            }
        }
        return $new_content;
    }