[Python-Dev] one last SRE headache

[Fredrik Lundh]

guido wrote:
> Suggestion:
> 
> If there are fewer than 3 digits, it's a group.
> 
> If there are exactly 3 digits and you have 100 or more groups, it's a
> group -- too bad, you lose octal number support.  Use \x. :-)
> 
> If there are exactly 3 digits and you have at most 99 groups, it's an
> octal escape.

I had to add one rule:

    If it starts with a zero, it's always an octal number.
    Up to two more octal digits are accepted after the
    leading zero.

but this still fails on this pattern:

    r'(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)(l)\119'

where the last part is supposed to be a reference to
group 11, followed by a literal '9'.

more ideas?

> (Can you even have more than 99 groups in SRE?)

yes -- the current limit is 100 groups.  but that's an
artificial limit, and it should be removed.

</F>