bug#16481: dfa.c and Rational Range Interpretation

[Jim Meyering]

On Sun, Feb 9, 2014 at 6:35 PM, Paul Eggert <address@hidden> wrote:
> Paolo Bonzini wrote:
>>
>> The correct course of action for grep is to defer range interpretation
>> to regex, because otherwise you can get mismatches between regexes with
>> backreferences and those without.
>
>
> It depends on what one means by "correct".  POSIX doesn't say what to do in
> this situation, so it's OK as far as POSIX is concerned for grep to use RRI
> in the typical case (i.e., without backreferences), and for grep to use some
> other interpretation in the rare cases when backreferences are used.
>
> The documentation for 'grep' attempts to address this issue, perhaps not as
> clearly as it could.  Maybe the installation instructions should talk about
> it as well, and suggest --with-included-regex for people who care about this
> sort of thing.

Has anyone looked at making glibc's regex use RRI?