On 26/03/2008, Xiaozhou Liu <[EMAIL PROTECTED]> wrote: > Hi Vimmers, > > During the development of the new regexp, one thing > confuses me a lot: ordered alternation. (e.g. given r.e. > 'ab\|abc' and text 'abc', 'ab' matched, not 'abc') > > I know that 100% compatibility is one of the project > goals. So I try to keep this feature in the new regexp. > But the problem is, ordered alternation is kind of 'side > effect' of the original back track regexp matcher. > AFAIK, It is very hard to implement this feature in the > new, truly NFA matcher, if it is not impossible. We can > resort to the original regexp when we see '\|', but we > don't solve the problem perfectly.
I thought Russ Cox had solved this in the code on his website, or am I mistaken? > So does anyone really need this feature to be kept? I don't need it, and though I'd prefer the longest match rather than the first alternative (as specified by POSIX) I don't really care too much as long as it is well documented. And since the original vi didn't have alternation, we don't need to worry about compatibility in that regard. > If so, please do tell me. For me, the removal of this > 'feature' won't break anything. It won't break anything that I use regexps for. But... I know Parsing Expression Grammars can make use of this feature to give precedence to one match over another. You might want to check whether any of the syntax files do something similar. --Antony --~--~---------~--~----~------------~-------~--~----~ You received this message from the "vim_dev" maillist. For more information, visit http://www.vim.org/maillist.php -~----------~----~----~----~------~----~------~--~---
