RE: [xml-dev] When is an XML vocabulary too complex? The art and science

["Len Bullard" <cbullard@hiwaay.net>]

Given a DTD and multiple sources for content, for any valid instance what is
the average time to code the instance given a measurable quality of coder?

It can be complex given the range of the set of valid instances required of
it.  The question is what is the cost of selection over the number of
options to find a valid solution given a candidate?  If the production of
the instance is constrained (ie, authoring enforces validity), then the
complexity is managed.  If not, it is discovered when the template is
created.

len

-----Original Message-----
From: Costello, Roger L. [mailto:costello@mitre.org] 
Sent: Saturday, February 25, 2012 1:43 PM
To: xml-dev@lists.xml.org
Subject: [xml-dev] When is an XML vocabulary too complex? The art and
science of creating large, complex vocabularies that are amenable to
teaching, learning, and using.

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. 

........

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?

..........

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.

..........

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







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