Una Smith wrote:

...

I'll second that. I use LaTeX, and previously used a precursor to SGML, to typeset all my printed documents. These *typesetting* languages are great for defining the appearance of the content of documents, but they are utterly inadequate for representing the content (ie., data) itself.

Jim Croft wrote:

This is not my understanding at all...

I thought the theory behind XML was to describe content, structure and relationships of data elements, quite independently of presentation as with typesetting languages...

Having defined an issue with XML, or similar, you can present it however you want...

Having defined an issue with a typesetting language, all you can do is typeset it...

Jim, I think your definition of a typesetting language is not the same as mine. If by "typesetting language" you mean RTF, then I would agree with you that XML is not a typesetting language. But I don't consider RTF to be a typesetting language because it cannot (to my knowledge) be used to write other languages. That's the important difference between RTF and XML (and LaTeX).

LaTeX is a language that was designed for typesetting, and it is good at it: typesetting is relatively painless, using LaTeX. LaTeX can be (and has been) used to write simple text-based user interfaces, and to write new programs (yes, you can write LaTeX programs to write LaTeX programs, ad infinitum; you could also write LaTeX programs to write C programs, and vice versa). These other uses of LaTeX are quite contorted, though; such programs are not pleasant to write.

GML was a markup language, like RTF; SGML and its derivatives, including XML, are (as I see it) typesetting languages.

Sure, if we all agree with Leigh Dodd that we are just using XML for the convenience of it (though I don't personally find XML convenient), that's okay. But the discussion here keeps slipping into implementation issues and forgetting about the underlying abstractions. We could conduct this discussion in PERL code too. (Hey, why not?) Why not forget the codes (or pseudo codes) and use ordinary words that we all understand? *Then* decide which language (if any) to implement it in, *after* we all agree what "it" is.

Una Smith una.smith@yale.edu

Department of Ecology and Evolutionary Biology Yale University New Haven, CT 06520-8106