Re: Document Engineering was RE: Way OT: Adam Smith and SoftwareMarkets

[Georg Bauhaus <sb463ba@d2-hrz.uni-duisburg.de>]

Robert C. Leif <rleif@rleif.com> wrote:
: I have published(1) on the semantic relationship of XML schemes to Ada
: specifications.
: <!ELEMENT   its-name  (its, content+, model, and-more*) >?
: I presume you do not use the formal => actual notation when you write Ada.

I do, but not at each and every opportunity.  If you allow me to be stubborn,
to me this notation would have to be taken further to mimick Schema
notation:

  call function => foo
       result_into => lhs
       passing (blurb => 5, other => "hox");

while readable, once you are familiar with procedure call notation,
this would seem overkill :-)

 
: book*  
: 
: less readable than
: 
:  name="book" minOccurs="0" maxOccurs="unbounded"? 
: Yes! A major requirement for source is readability. You overloaded "*".

Frankly, in a DTD I cannot think of * as anything but a Kleene
star inspired occurence indicator, and in XML I don't think of
'<' as an overloaded operator, but as a start tag open character,
similarly for '>'.  In fact, in XPath  predicates '>' *is*
overloaded in this sense.

Admittedly, it does need learning to write DTDs, and learning the
meaning of the (few) symbols, but just because Schemata don't use
the same symbols, but others for XML syntax and patterns, they won't
free us from a similar learning effort. Neither will they reduce
the complexity in trying to understand the structure defined in
a Schema. At least I don't see how they could.

: Admittedly, XML is more verbose than Ada. However, I do not accept the
: argument that I should write in C because Ada is more verbose than C.

I think the comparison might be a bit unfair. The concrete syntax for
DTDs is far less affected by the properties of C syntax that make it
confusing. For example, '+' has one meaning, as does '*'. Compare this
to '+', '++', and '*' in some context.

: (1)R. C. Leif, SIGAda 2001 Workshop, "Creating a Symbiotic Relationship
: Between XML and Ada" Ada Letters Vol. XXII, pp 24-41 (2002).


I've got hold of a copy, for the weekend.

-- Georg