Re: [PATCH 2/4] log and rev-list: Fixed newline termination issues with --graph

From: Jakub Narebski <jnareb@gmail.com>
Date: Apr 7, 2008, 13:19 UTC
Message-ID: <m3hcedu7kd.fsf@localhost.localdomain>
In-Reply-To: <7vwsnaoxlz.fsf@gitster.siamese.dyndns.org>

Junio C Hamano <gitster@pobox.com> writes:

Show 19 quoted lines

> Junio C Hamano <gitster@pobox.com> writes:
> 
> > I suspect that --pretty=format: (i.e. userformat) should have a way to
> > explicitly tell which is wanted.  Perhaps we can keep the separator
> > semantics not to break existing users, and introduce a dummy expand item
> > (say, '%_') and when it appears in the pattern it would ask for the
> > terminator semantics instead?
> >
> > In any case, I'm happy to see that somebody started looking into this, as
> > this "separator vs terminator" issue in userformat has been nagging me for
> > quite a while.  It might be good idea to have the change independently
> > from the graph extension first and then build the graph stuff on top of
> > the solidified base.  I dunno...
> 
> Some alternatives to specify terminator semantics I considered are:
> 
>  (1) Presence of %_ in "--pretty=format:..." triggers terminator
>      semantics and %_ itself interpolates an empty string; otherwise
>      separator semantics is used.

Or %_ might interpolate to _single_ separator, swallowing all
separators that follows it (something like collapsing whitespace).
Either that, or %_ interpolate to separator value, and %*_ collapses
separators (terminators).
 
Bit less hacky, bit more geeky.

>  (2) Presence of %n in "--pretty=format:..." means a multi-line output and
>      uses separator as before; lack of %n means it is a one-line format
>      and uses terminator.

I guess that literal newline in format would also mean multi-line output. Also '%b' (body) should mean multi-line output.

BTW. rpm uses [% ... ] to iterate over a set of (parallel) arrays in --queryformat, which is a bit similar to --pretty=format:<fmt>, e.g. 'rpm -q --queryformat "[%-50{FILENAMES} %10{FILESIZES}\n]'

BTW2. git-for-each-ref uses _different_ kind of format, %(<name>) and not %<char>.

Show 14 quoted lines

>  (3) A new option --pretty=tformat:... (i.e. tformat instead of format)
>      means LF (or NUL) is used as terminator instead of separator;
> 
>  (4) A new syntax --pretty=format/... (i.e. slash instead of the usual
>      colon) means LF (or NUL) is used as terminator instead of separator;
> 
> The first one is what I suggested in the message, but it feels somewhat
> hacky.  I suspect that the second one would catch 99% of the cases, but it
> is DWIM and it is known that DWIM can go wrong.  I favor design along
> the lines of (3) or (4), which I think would be much cleaner.
> 
> I however do not particularly like either "tformat" which is a non-word,
> nor ":" vs "/" whose differences do not intuitively translate to
> "separator vs terminator" distinction.

"|" instead of ":" wouldn't be a good idea?

-- 
Jakub Narebski
Poland
ShadeHawk on #git