Re: [PATCH/RFC v2 0/2] add regex match flags to git describe

> On 01/04/2016 06:46 PM, Junio C Hamano wrote:
>>>> Magic pattern annotation like we do for pathspecs Duy raised may not
>>>> be a bad idea, either, and would probably be easier to teach people.
>>>> Just like in Perl "(?i)$any_pattern" is a way to introduce the case
>>>> insensitive match with $any_pattern, we may be able to pick an
>>>> extensible magic syntax and decorate the pattern you would specify
>>>> for matching refnames to tell Git what kind of pattern it is, e.g.
>>>>
>>>>     $ git mgrep -P -e foo --refs '/?glob/release_*'
>>>>
>>>> I am not suggesting that we must use /?<pattern type name>/ prefix
>>>> as the "extensible magic syntax" here--I am just illustrating what
>>>> I mean by "extensible magic syntax".
>>>
>>>
>>> I hadn't seen the pathspec magic patterns before- interesting.  We
>>> could possibly share syntax with pathspecs, ie
>>> :(?pattern-options...)pattern
>>
>>
>> Even though we have DWIM between revisions and paths on the command
>> line when the user omits "--" for disambiguation, I do not think we
>> look at the shape of the string to DWIM/decide that it is a pattern,
>> so as long as the magic syntax cannot be a valid pattern to match
>> against refs right now (and your ":(?...)"  qualifies as such, as a
>> refname would not contain a component that begins with a colon), it
>> would be possible to introduce it as the magic syntax for matching
>> refs.
>>
>> Or did you mean to use this syntax also for patterns that match
>> strings in contents, e.g.
>>
>>      $ git grep -e ':(?perl-regexp)...'
>
>
> I think it would be nice to support this syntax in every command that does
> pattern matching.
>
> Corner case: what if we want to search for ":(?perl-regexp)", eg in git's
> own source?  I suppose this would do:
> git grep -e ":(?fixed-strings):(?perl-regexp)"