a very common use case for regexes is to find matches that are preceded or followed by some context. a classical example being all lines that end with ‘a’. this requirement is usually expressed with a lookahead, where upon finding an ‘a’, you look ahead to check if it’s the end of the line. in a backtracking engine, this is very easy to implement - you just duct-tape the logic that checks the next character, but in a DFA-based engine, this is impossible because you cannot report “the match is here” if the next character is not even known yet. and by the time you know the next character, the position information is lost, so you can’t report the match retroactively (well, unless the distance is fixed of course..).
В России впервые с 1986 года введут новый ГОСТ на белый хлеб02:05。WPS下载最新地址是该领域的重要参考
Что думаешь? Оцени!。爱思助手下载最新版本是该领域的重要参考
Студенты нашли останки викингов в яме для наказаний14:52，推荐阅读夫子获取更多信息