Re: [PATCH] pathspec: rename per-item field has_wildcard to use_wildcard

[Michael J Gruber <git@drmicha.warpmail.net>]

Junio C Hamano venit, vidit, dixit 06.04.2011 19:13:
> Nguyen Thai Ngoc Duy <pclouds@gmail.com> writes:
> 
>> 2011/4/6 Junio C Hamano <gitster@pobox.com>:
>>
>> I have started working on the conversion, but it may take a while
>> because in many places pathspec is still assumed a prefix (and handled
>> separately, which is not good for negative pathspec). Fundamental
>> support for magic pathspec and "top dir" notation probably do not need
>> get_pathspec() converted to struct pathspec.
> 
> I think you meant to say "If we only want to have 'top dir' magic,
> fundamental support and get_pathspec() conversion are unnecessary", and I
> agree 100%.
> 
> I am actually tempted to add Michael's hack to get_pathspec() only to
> support the "from the top" (and error out with any other magic---as the
> approach without a proper restructuring will not work with anything but
> that particular magic), to get the "add -u" topic going, and let you (or
> other people who are interested in the pathspec rationalization) later fix
> it up just a small part of existing issues.
> 

Junio, we're in rc phase ;)

> The extensible syntax I have in mind (we only parse in get_pathspec() in
> such a tentative version but anything other than the :/ will error out) is
> to use:
> 
>  (1) Colon, a run of selected non-alpha (i.e. magic signature), an
>      optional colon to terminate the magic signature, followed by the
>      path, e.g.
> 
>      - ":/hello.c" is a path from the top.
> 
>      - ":!/hello.c" is path from the top but no globbing.
> 
>      - ":/!hello.c" is the same as above.
> 
>      - ":/::hello.c" is ":hello.c" from the top, the second colon
>        terminates the magic signature and allows the funny file with a
>        leading colon to be named.
> 
>      - "::hello.c" does not have any magic, is the same as "hello.c".
> 
>  (2) Colon, open parenthesis, a comma separated list of words to name
>      magic, close parenthesis, followed by the path, e.g. these are the
>      long-hand counterparts to the examples in (1)
> 
>      - ":(top)hello.c"
>      - ":(top,noglob)hello.c"
>      - ":(noglob,top)hello.c"
>      - ":(noglob,top):hello.c"
>      - ":()hello.c"
> 

Do we need the parentheses? I guess we need them to have the magic start
with a non-alpha, otherwise we could do with ":top,noglob:hello.c"
(which I like but breaks those with a file named ":top:hello.c").

What about these:

:/(noglob)hello.c
:(top)!hello.c

I.e. do we allow combinations?

Do we need the the second colon at all then? I.e. we can declare ":"
non-magic after seeing it once so that ":(top):hello.c" would be
":hello.c" at top.

> At this point, I am not interested in building the repertoire of magic
> yet, but would want to nail a syntax that is
> 
>  - concise in common cases (e.g. "from the top, not a funny name" is ':/'
>    followed by the name);
>  - is extensible in the future; and
>  - easy to parse and error out on magic we do not understand.
> 

- and does dot break users with files named xyz.

Spelling out xyz would already nail down the syntax quite a bit. It
seems you accept to break people with files named ":(top)hello.c" but
not those with files named ":top:hello.c". Which is OK if it's a
conscious decision, of course.

Michael