SGML Compatibility

Of our design goals, this proved to be most troublesome in practice. Our subgoals included:

  1. Existing SGML tools will be able to read and write XML data.
  2. XML instances are SGML documents as they are, without changes to the instance.
  3. For any XML document, a DTD can be generated such that SGML will produce "the same parse" as would an XML processor.
  4. XML should have essentially the same expressive power as SGML.

That we largely succeeded in accomplishing these goals is due to two factors. First, the determination of many members of the WG and SIG to stick with SGML compatibility, even when there were good design reasons for abandoning it. Second, the active participation and co-operation of the SGML community, led by Charles Goldfarb, in ensuring that the load of ensuring that XML and SGML remained compatible was shared by both parties.

Back-link to spec

Copyright © 1998, Tim Bray. All rights reserved.