Re: Help me please ^^

Ben Schmidt wrote:
> [Resending to the list. Originally from BPJ.]
>
> 2011-05-04 01:03, Ben Schmidt skrev:
>>> perl returns '1a11c1', BTW!
>>
>> Mmm. It's a bit debatable whether the second 1 in the 11
>> represents an
>> overlapping match or not. That's the problem with zero-length matches
>> that aren't solidly anchored; there are a lot of funny edge cases.
>
> Apparently there's one match for "b" and one match for
> the nothing between b and c. Rather what you would
> expect from a pattern which essentially means "match
> any number of b's or nothing": every b and every
> non-character position in the string abc has indeed become
> 1.
>
> 2011-05-04 07:11, Ben Schmidt skrev:
>> Vim's regular expressions are far from standard. Just
>> browse pattern.txt and you will see many oddities
>> documented or demonstrated, as well as many
>> extensions to facilitate things such as syntax
>> highlighting. I'm pretty sure most other Vi and Vi
>> clone programs have their own oddities, too.
>>
>> I'm not sure whether Sed or Perl is more 'correct'. I
>> haven't read any POSIX specs.
>>
>> Ben.
>
> I've never heard that Perl is trying to follow any
> POSIX standard any more than Vim. Even a quick look at
> the Perl 6 regex specs shows that Larry and the gang
> are indeed doing what they please, leading the way
> rather than following.
There's probably a history of regular expressions somewhere; ed
definitely preceded (the original) vi, and I think sed did, too. Awk
followed in sed's "footsteps", and Perl came after vi. Vim follows vi's
reg-ex (with extensions) handling. Anyway, I don't think the various
programs' reg-ex styles are going to merge because that would invalidate
a lot of scripts, so claiming that "X's style is better than Y's style"
isn't going anywhere. IMHO Vim did it the right way -- that is, it
extended earlier reg-ex handling, not changed it (like Perl did).

Regards,
Chip Campbell

--
You received this message from the "vim_use" maillist.
Do not top-post! Type your reply below the text you are replying to.
For more information, visit http://www.vim.org/maillist.php