Xiaozhou Liu wrote:
> 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. > > So does anyone really need this feature to be kept? If so, please do tell me. > For me, the removal of this 'feature' won't break anything. It is close to impossible to check that a change like this doesn't break existing scripts. And when something breaks, e.g. a syntax file, a normal user is very unlikely to be able to figure out what caused the problem. I stick to the opinion that the new regexp engine must work exactly like the existing one. Most things can be made to work that way. I also thought that this behavior of an alternate branch could be made to work in a DFA, with some effort. And otherwise we would have to fall back to the old engine when there is an alternate branch in the regexp. -- hundred-and-one symptoms of being an internet addict: 174. You know what a listserv is. /// Bram Moolenaar -- [EMAIL PROTECTED] -- http://www.Moolenaar.net \\\ /// sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\ \\\ download, build and distribute -- http://www.A-A-P.org /// \\\ help me help AIDS victims -- http://ICCF-Holland.org /// --~--~---------~--~----~------------~-------~--~----~ You received this message from the "vim_dev" maillist. For more information, visit http://www.vim.org/maillist.php -~----------~----~----~----~------~----~------~--~---
