[Zope] sort_link

I'd like to make a list of items returned by Zcatalog sortable by different criteria, like the how-tos on zope.org.. The user should be able to click on a headline, and the returns will be sorted by that variable. as "sort=" doesn't take expressions, i am puzzled on what to do.. Way back in the list-archives, there is mention of a product called Zieve, but i find no reference to it on the zope site. There is also the magic "sort_link" -variable used to do this on Zope.org.. What is it ? An external method ? ------------------------------------------------ Geir B Hansen geirh@funcom.com Web-designer / Graphic artist Funcom Oslo ------------------------------------------------