Re: [xml-dev] RE: Declarative programming requires a different mindset

[Kendall Shaw <kshaw@kendallshaw.com>]

"Costello, Roger L." <costello@mitre.org> writes:

> People have said that a programming language is one that can solve
> many different kinds of problems. Certainly, then, XSD is not a
> programming language.

I don't think your basic question about declarative programming is
answered very well yet. Or, at least, I don't fell like the questions
are resolved for me. Maybe you should also ask your questions in a
functional programming group.

Coining a term does not cause there to be coherent or valid concepts
related to it. The point someone was making when coining the term does
not necessarily relate to other conversations using the same term.

Writing a schema is programming. And, XSD is a language. XSD is not a
general purpose programming language. So, I don't know what to make of
the bubble outside of XSD and programming languages.

A program is the specification of a result. Creating a style in a GUI is
programming, e.g. selecting italic for paragraphs when they occur within
a quotation. That style of programming is declarative. Soldering wires
into a circuit board is also programming.

Using generalized markup is part of a declartive programming
process. Instead of writing code that specifices an explicit procedure
for rendering an output, the output is described. Or, the most powerful
parts of the program are specified declaratively. The languages used in
specifying such a program can be things like relax ng, xslt, html etc.

These to programs could specify the same result:

<doc><heading/><form/></doc>

(doc (heading) (form))

Regardless of whether either language is general purpose or not, they
are being used declaratively.

Kendall