Re: [Gnu-arch-users] Re: File-tpye plug-in architecture for Arch?

[Tom Lord]

    > From: Thomas Zander <address@hidden>

    > On Monday 22 December 2003 16:23, Andrew Suffield wrote:
    > > > Could you point out what the expected result would be since I see no
    > > > difference between this and the plain-text approach of merging.

    > > Well, duh. That's because diff(1) doesn't understand it either. By
    > > pure heuristics it happens to do the right thing more often than not
    > > for source code and english text. It's wrong for almost everything
    > > else.

    > XML is very very different from binairy text; as applications will ignore 
    > ordering of Elements when ordering is not needed so you are allowed to 
switch 
    > ordering without anything breaking (for example)

Asuffield delights in being terse yet correct.  He is talking over
your head.


    > I find it quite annoying that you (plural) simply tell others they are 
wrong 
    > since you can't see how the solution could work.

You're making fundamental, non-obscure, mathematically certain errors
in your proposed solutions.  "We" find it annoying to have to point
this out again and again.

But let me try again anyway.

OO document bundles can contain a "meta.xml" file.   The contents of
that file are constrained to an XML subset defined by a DTD.

Pick your favorite generic XML-diff/patch tool and tell me under what
conditions it is 

(a) guaranteed to produce an XML document valid under that DTD when
    applying diffs between meta.xml versions A and B to a meta.xml
    version C.

(c) guaranteed to produce a meta.xml output which is not only valid 
    but useful

(d) guaranteed to produce byte-wise identical-to-B output when
    applying the diff between versions A and B to A.


Repeat that for each of the other XML-subset types used in OO format.

At _best_ (from your perspective): you have expressed a _hope_ that
these questions have good answers; asuffield (and others) have given
plausible arguments (very nearly proofs) that those questions _don't_
have good answers.

And at _second_best_ you are backtracking to say "well, we won't use
the XML-diff/patch tools for _that_" but then why would we bother with
them at all when ordinary diff or xdelta would do just as well for the
more restricted purposes?


-t