4 ms·

I have no idea what you're talking about. My point is more pragmatic the regex /A/ will match the string "QQQQ" and this tool doesn't take that into account.

• takeda 12y ago
  Actually this is wrong, when you use A* in vim for example you're not looking exactly for A* but for substring containing an A* since this also matches "" programs like vim will match anything. Just because these tools use regex this way doesn't mean that's how regex really works.
• mgraczyk 12y ago
  No, it doesn't. It matches the empty string at the beginning of 'QQQQ', not the Qs themselves: /A*/.exec('QQQQ') [""] When computer scientists discuss what a regular express does and does not "match", they are saying that strings which are "matched" by a regex are those strings which are members of the regular language defined by the regex. QQQQ is not a string in the language defined by /A* /, so /A* / does not match QQQQ. If we look at things your way, we would have to say that the regex /A/ matches "AQQQQ". It does not. It matches "A".