Can CML be extended?
CML can also support more complex chemical concepts such as reactions, chemical grammars (e.g. Markush structures and combinatorial chemistry) and chemical queries (substructure searches). The final design of these will depend on the syntax and support for XLINK and when these W3C recommendations are available, these topics will be published in following articles. We note with approval the concurrent publication of XyMML, an XML-based language for typesetting chemistry and discuss its relationship to CML in this article.