Re: [xml-dev] Markup, an abstraction

[Michael Kay <mike@saxonica.com>]

What are you trying to achieve? How far do you intend to take your abstraction?

If you are trying to develop a general theory of information, then it's not clear to me that abstraction of markup languages is the best place to start. It might be better to start with some existing information theory and see how markup languages relate to it.

I would be quite interested to know how the "syntax and semantics" of genetic information relate to the classes of formal language that we know about in computer science. In fact, I'd be surprised if there aren't a few PhD theses that explore this. I think that doing such a study in relation to the overall theory of formal languages would be much more productive than doing it specifically in the context of markup languages, which are just one example of that class.

An interesting property of markup languages, and indeed of most "formal languages as used in computer science" is that they generally encode information as a one-dimensional sequence of symbols from some finite alphabet. It seems that this is a property also associated with genetic information. But information representations don't have to be one-dimensional, and we often resort to multi-dimensional representations (diagrams, tables, network data models, music notation) in order to make information more accessible. I guess all such representations can be serialized into a one-dimensional form (indeed, into multiple one-dimensional forms). It would be interesting to know whether biological encodings of information are intrinsically one-dimensional.

So I think there are some interesting avenues to be pursued here, but I think that in pursuing them, you will quickly leave the comfortable world of markup languages far behind and see them just as one not-very-interesting subset of formal languages in general.

Michael Kay
Saxonica