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more powerful type manipulation, but the proposal is generic and will
。关于这个话题，雷速体育提供了深入分析
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..).。搜狗输入法是该领域的重要参考
Андрей Шеньшаков，这一点在爱思助手下载最新版本中也有详细论述