Patent fun: Microsoft Word sales banned in the US

US Patent 5,557,722 (based on a product released in late 1990) discloses an SGML-based system that stores the tree structure, the element-types, the style information, and the content in entirely separate, interconnected files. That system allowed the end user to completely swap stylesheets at any time. There are many other patents related to the same system.

That patent also cites about 35 pieces of prior art, much of which also seems to me directly relevant; some of which include editing as well and some of which goes relevantly back to 1979. Having been the primary architect of that system, I can say with certainty that the notions of separating structure and content, doing so for arbitrary DTDs, and being able to change style, structure, and content separately, were all well-known and implemented at the time in the SGML world (which obviously bears directly on XML).

I haven't analyzed the new patent in depth, but from the abstract and the discussions, this seems to me pretty definitive prior art. I wonder if it came up in the case?

Steve