Re: Dealing with character ranges in grep

[Jim Meyering]

Johannes Meixner wrote:
> Hello Jim,
>
> On Jun 16 10:44 Jim Meyering wrote (excerpt):
>>>> Thus, if we go this route, we are effectively saying
>>>> that people who want self-consistent regex-handling
>>>> in our tools must build with --with-included-regex or end
>>>> up causing subtle problems.
> ...
>>> It goes like this (at least for gawk, grep and sed):
>>>
>>>   change how dfa.c interprets ranges like [a-z]
>>>   change how gnulib's reg* code handles ranges
>>>
>>> Always use the included regex code (the one from gnulib),
>>> so that its interpretation is consistent with that of dfa.c.
>>>
>>> Grep's current upstream default is to build --with-included-regex,
>>> which makes grep use glibc's regex code.

Hi Johannes,

> Isn't there a typo?
>
> Shouldn't it read
>  "Grep's current upstream default is to build --without-included-regex,
>   which makes grep use glibc's regex code."

Yes, you're right.  Thanks for pointing that out.

> At leats for grep-2.7 "configure --help" shows me:
> -----------------------------------------------------------------------
>   --without-included-regex
>         don't compile regex; this is the default on systems
>         with recent-enough versions of the GNU C Library
>         (use with caution on other systems).
> -----------------------------------------------------------------------
>
> Or do I misunderstand something here?
>
>>> To make this proposed change go through, that configure-time option would
>>> have to be eliminated, so that we always build with the gnulib-provided
>>> regex code.  Of course, if glibc ever changes, we can detect that and
>>> automatically prefer it when possible.
>>
>> For the record, at least Fedora's grep and sed both build
>> --without-included-regex, so would be affected.
>
> Same for openSUSE and all the "Suse Linux Enterprise" products.
>
>
> Kind Regards
> Johannes Meixner