From: Andreas Ericsson <ae@op5.se>
Date: Thu, 18 Sep 2008 08:06:28 GMT
Subject: Re: [PATCH 2/4] diff.c: associate a flag with each pattern and use it for compiling regex
Message-ID: <48D20C04.1020703@op5.se>
In-Reply-To: <7vod2myljk.fsf@gitster.siamese.dyndns.org>

Junio C Hamano wrote:
> Andreas Ericsson <ae@op5.se> writes:
> 
>> Junio C Hamano wrote:
>> ...
>>>>  static struct funcname_pattern {
>>>>  	char *name;
>>>>  	char *pattern;
>>>> +	int cflags;
>>> What does "C" stand for?
>> "compile". It's the same name as regcomp(3) uses for the flags being
>> used to compile the regular expression. The full mnemonic name would
>> be regex_compile_flag, which is a bit unwieldy. Perhaps regcomp_flags
>> would be a good compromise?
> 
> Ah, I see.
> 
> When I saw that new field for the first time, I didn't think it will be
> used to store the bare flag values regcomp/regexec library would accept
> directly (I expected we would see #define or enum to tweak our own set of
> features, not limiting ourselves EXTENDED/ICASE etc. that regcomp/regexec
> library supports)
> 
> IOW, it just did not click for me to look at "man 3 regcomp" which says:
> 
>     int regcomp(regex_t *preg, const char *regex, int cflags);
> 
> So unless others feel that we might get a better layering separation by
> not storing REG_EXTENDED and stuff directly in that field (which was my
> initial reaction without looking at 4/4 which does store REG_EXTENDED
> there without our own enums), cflag is perfectly a good name here.
> 

I think it makes perfect sense to use whatever we pass when compiling
the regex. I wouldn't dare try to hack up something that pre-mangles
a regular expression and assume it gets it right everywhere anyway, so
I'm quite happy with leaving it all to regcomp(3) and friends.


> Thanks --- I am bit under the weather and not thinking quite straight.
> 

Mix 2cc's of 7yo Havana Club into a large cup of tea. Drink one such
cup every hour and eat a fresh fruit with it. I haven't been ill a day
in my life since I came up with that most excellent cure for absolutely
everything. If nothing else, it makes it a bit less boring to be ill.

-- 
Andreas Ericsson                   andreas.ericsson@op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231