Constraint Logic Programming

Hi all,

I noticed recently that SWI Prolog has CLP over rationals and _reals_, which, to my knowledge, is sg. great and not so common. But... I am not familiar with CLP. Is there some intro, maybe tutorial what I can see, from an IT developer point of view? (the articles shown up by Google are more or less academic (which is good:)...)

I looked for SWI Prolog CLP libraries documentation, but I found only reference descriptions.

Can you recommend something?

thanks,
   Zsolt