[Python-Dev] one last SRE headache

[Tim Peters]

[/F]
> 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'.

But 9 isn't an octal digit, so it fits w/ your new rule just fine.  \117
here instead would be an octal escape.