[xml] Regarding xml diff features in libxml (was Re: [xslt] patch - xsltAttrListTemplateProcess)

[Malcolm Tredinnick <malcolm commsecure com au>]

Hi Mark,

On Thu, 2004-09-30 at 07:27 -0700, Mark Vakoc wrote:
[...]
> On an unrelated node would you have an objection to adding a unsigned long
> member to the xmlNode struct?  I plan on implementing the xmldiff capability
> along the lines of Microsoft's program and this member would be used to hold a
> hash of the node for quick comparisions.  The hash for a node is generated by
> the node's content including it's children.  I suppose I could use _private but
> would prefer to keep that available outside the library.

If you are going to look at this, could you start a discussion at some
point on xml gnome org about what APIs might be useful here. I have no
idea what Microsoft does, but I am familiar with a couple of other
xmldiff programs as well as having written a slightly lame version
myself for a restricted set of documents.

My feeling is that getting a reasonable public API for this is going to
be fiddly, since there are a number of time/space/"coherency" (the last
one referring to trading off "reasonable-looking" diffs against smaller
changesets) trade-offs depending upon the algorithms used and it would
be nice to be able to configure this -- even if we choose a reasonably
quick and decent version for the default.

I have not really tried to work out what might be a good API here, but I
would like to help out with the design of one.

I've added xml gnome org to the CC list here, so maybe we should move
this over there.

Cheers,
Malcolm