lib/Bob/FileTask.php
function getTimestamp()
    {
        $lastModifiedTimes = iterator_to_array(itertools\filter(itertools\map(
            function($file) {
                if (file_exists($file)) {
                    return @filemtime($file);
                }
            },
            $this->prerequisites
        )));

        if ($lastModifiedTimes) {
            return max($lastModifiedTimes);
        }

        return 0;
    }
function getTimestamp()
    {
        $lastModifiedTimes = iterator_to_array(itertools\filter(itertools\map(
            function($file) {
                if (file_exists($file)) {
                    return @filemtime($file);
                }
            },
            $this->prerequisites
        )));

        if ($lastModifiedTimes) {
            return max($lastModifiedTimes);
        }

        return 0;
    }
# Returns the time as Unix Epoche represented by an Integer.