Re: [PATCH] Quick description of possible gitattributes system

From: Andy Parkins <andyparkins@gmail.com>
To: git@vger.kernel.org
Cc: Junio C Hamano <junkio@cox.net>
Subject: Re: [PATCH] Quick description of possible gitattributes system
Date: Fri, 2 Mar 2007 08:56:31 +0000	[thread overview]
Message-ID: <200703020856.35246.andyparkins@gmail.com> (raw)
In-Reply-To: <7vejo8o69o.fsf@assigned-by-dhcp.cox.net>

On Friday 2007 March 02 00:09, Junio C Hamano wrote:

[deleted lots of easily-agreed-with stuff]

> I would suggest making handler section _match_ the attribute
> names.  By "match", what I mean is to allow something like this:

I don't see that working.  If it were possible to do that why would we need 
separate handlers and attributes?  You're example is fine

> 	[handler "image/*"]
>         	pretty = "cmd display -"

But what about when I want to do this:

[handler "lossless-images-only"]
   attribute = "image/png"
   attribute = "image/gif"
   pre-commit = /bin/false

To prevent the adding of all lossless image formats?  I actually can't see a 
time when the handler name needs referencing, so it can be anything (as long 
as it's unique - perhaps).  If you wanted to use/encourage the attribute 
name - fine, but it shouldn't be required.  However I think it's more 
sensible to name the handler after what it does than what it applies to - the 
applies to can change, what it does never.

The handlers are like function calls.  You wouldn't want to name functions 
after where they were called.

> > +[handler "show-images"]
> > +  attribute = image/gif
> > +  prettyfilter = pipe display -
>
> I would recommend against calling them *filter.  After all, the
> semantics of each handler action (such as input, output and
> pretty) already determine if it needs to act as a filter or data
> sink.  We do not need to say prettyfilter either; it is not even
> a filter to begin with -- it is a data sink.

That's true; I don't have any strong feelings.  I just didn't like "convert" 
being used.  Convert always sounds like something that takes one thing and 
makes another out of it - at the end you have two things.  Filters transform 
one thing into another - at the end you have one thing.

Perhaps better names would be simply to name them after the operation the runs 
them.

 infilter = checkin
 outfilter = checkout
 prettyfilter = show

?

Is the document useful; would you like me to maintain it?  I don't want to 
waste your time with it.

Andy
-- 
Dr Andy Parkins, M Eng (hons), MIET
andyparkins@gmail.com