Re: Review of "Storing Data in Documents"

Graham Klyne wrote:

 > In short, as I understand the term, "declarative" can be "Turing
 > complete".  I thought that was what XSLT (along with functional
 > programming languages) actually achieves.

XSLT is functional. It is not declarative. SQL is declarative*, and it 
isn't Turing complete. It might be possible to make a declarative 
language Turing complete, but I'm not sure what the point would be. The 
goal of a declarative language such as SQL is to describe the result you 
want and allow the computer to determine the algorithm it uses to 
calculate that result. Programming in a Turing complete language 
generally involves specifying an algorithm.


* People do argue that SQL isn't truly declarative, but it's as close as 
any major language a lot of people are likely to know.

-- 
Elliotte Rusty Harold  elharo@metalab.unc.edu
XML in a Nutshell 3rd Edition Just Published!
http://www.cafeconleche.org/books/xian3/
http://www.amazon.com/exec/obidos/ISBN=0596007647/cafeaulaitA/ref=nosim

Received on Wednesday, 23 March 2005 12:49:34 UTC