RE: Principle of Least Power (was Re: Agenda of 7 February 2006 T AG teleconference)

On Tue, 2006-02-07 at 13:43 -0600, Bullard, Claude L (Len) wrote:
> I wish there were language comparisons that grounded this 
> principle in examples.

The draft gives a number of examples, no?

"A bug-free regular expression processor, for example, is by definition
free of many security exposures that are inherent in the more general
runtime one might use for a language like C++."
"HTML for example, is intentionally designed not to be a full
programming language ..."
 -- http://www.w3.org/2001/tag/doc/leastPower.html


>   To repeat from XML-Dev:
> 
> When selecting a language, how does one know when it has the 'least power'?
> 
> o  Is Assembler less or more powerful than C?
> 
> o  Is C less or more powerful than C++?
> 
> o  Is Lisp less or more powerful than Prolog?

Those are all turing-complete; equally expressive.

> o  Is RDF less or more powerful than Conceptual Graphs?

Pretty close... I think CGs have universal quantification
where RDF does not; I'd have to double-check.

> o  Are Conceptual Graphs more or less powerful than Topic Maps?

My repeated attempts to ask that Topic Maps be specified
w.r.t. traditional structures so that I could make such
a comparison have yielded unsatisfactory results.
I don't know what the expressive capability of Topic Maps is.

> o  Are DTDs less or more powerful than Schematron?

Schematron is turing-complete, as I understand. DTDs are not.

> A principle or axiom is of no value without the rules for applying it. 
> At least some examples?
> 
> len

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
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