On 8/28/06, Jay R. Ashworth jra@baylink.com wrote:
Because in wikitext, everything is in-band; in XML, the structure is out-of-band, on purpose. This requires an entirely different, and I suspect, much more complicated diff algorithm.
I don't know what "in-band" and "out-of-band" mean ([[Out of band]] doesn't help either), but if the diff engine parses the XML, it can look for a) changes in structure/markup and b) changes in content. Either one should be very easy and fast to diff, given XML-parsing library functions (for the C++ module used on WMF sites, that is). Faster than present, I don't know, but the present differ is hardly a bottleneck.