When is an XML vocabulary too complex? The art and science ofcreating la

["Costello, Roger L." <costello@mitre.org>]

Hi Folks,

If an XML vocabulary is large and complex, does that mean it's bad?

Calculus is a large and complex field of mathematics, does that mean Calculus is bad? Obviously not. 

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I am reviewing a large and complex XML vocabulary.

Actually, I superficially reviewed it a few years ago and came to the judgment, "This is too complex, it's no good."

Now I am patiently reviewing it in depth.

The vocabulary has a lot of optional elements and attributes, so I am focusing on just the mandatory stuff and getting a firm understanding of it. 

Gradually, as the need arises, I will pick up the optional stuff.

I've noticed that many Calculus books introduce the core concepts first and then describe the "non-core concepts" in later chapters. Presumably that makes it easier to learn Calculus.

Is optionality in XML vocabularies the markup equivalent of "non-core concepts" in textbooks?

In August there will be a conference on "What is Good XML?" 

Perhaps a characteristic of "good XML" is the frequent employment of optionality in elements and attributes?

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Calculus is very useful. It's used in everything from calculating the motion of planets to building bridges.

But if all Calculus textbooks were written in a way that nobody could understand then I suspect that it wouldn't matter how useful Calculus is, it wouldn't be used.

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You may create the world's most useful XML vocabulary. 

But if nobody can understand it and teachers can't explain it then it won't be used.

So, the design of an XML vocabulary involves more than usage. It also involves education and elucidation. Without the latter two, the former is for naught. 

Using optionality as a means of expressing "Hey, this is non-core information. You can learn it later if you need it" seems to be fundamental to the art and science of creating large, complex vocabularies.

What do you think?

/Roger