[jeswin]

> Java+XML and CSS — both of these were hailed as declarative breakthroughs originally, and today they are the stuff of “TheDailyWTF” nightmares.

Java+XML isn't declarative, XSLT was. XSLT declined when XML declined. CSS works quite well even today and is still widely used.

Declarative coding style is in many ways resistant to obsolescence since you're just declaring what you want than how to do it. The best example is SQL; mostly unchanged in decades.

[pavlov]

XML is certainly declarative.

As far as CSS goes — ask any front-end web developer if they would like all programming to be more like CSS...? It is a collection of thousands of properties, often overlapping or contradictory, some with their own sublanguages for further specification, and many features are defined as hidden side effects of one property when nested inside another. A total mess.

You can only declare what you want if the language lets you say it. (Think of Wittgenstein’s famous maxim.) SQL was a great design informed by decades of research. Most software designs are not like that, unfortunately.

[tannhaeuser]

I'm a fan of declarative (eg. logic) programming but how is XSLT declarative when Java and XML isn't? XSLT has been proven Turing-complete a long time ago (eg. [1]), and if anything, is functional, being derived from DSSSL/Scheme up to the XML syntax.

[1]: http://conferences.idealliance.org/extreme/html/2004/Kepser0...).