The Zope Presentation Templates project is underway to develop a next-generation template technology for Zope* that is XHTML-compliant and which makes it easier for designers to work with. However it is hoped to design it in such a way that as much as possible is not specific to Zope, in the belief that the technology is more widely useful and could be adopted by other languages and tools. I'm extending an invitation (in a personal capacity rather than as an official spokesman for the project) to developers from other communities to consider contributing to the design of ZPT to help keep it language-independent, and to consider implementing the approach in their programming language of choice. First of all some background on what I mean by "next-generation". In the beginning programmers wrote program code with embedded HTML. Then technologies like eperl, ASP, JSP and PHP allowed us to reverse this and to embed program code in the HTML. However a school of thought wanted to have greater separation of presentation and logic, and so various template mechanisms were devised that provided just enough programmability to control presentation, but which moved the business logic out elsewhere. One example of this approach is Freemarker: <h1>$customername</h1> <table border="1"> <tr> <td>Date</td> <td>Amount</td> </tr> <list deposits as deposit> <tr> <td>${deposit.date}</td> <td>${deposit.amount}</td> </tr> </list> </table> Instead of custom tags, some other template mechanisms use special markers to designate control structures, but most template mechanisms share the property that their templates are not compliant with XHTML (though the rendered output may be). As such it can be awkward trying to use such template mechanisms with authoring tools that only understand XHTML. The approach that the ZPT project is pursuing is to attach the control-flow, formatting and placeholder directives as attributes of standard XHTML tags. The example above becomes something like: <h1 zpt:insert="customername">Bob Smith</h1> <table border="1"> <tr> <td>Date</td> <td>Amount</td> </tr> <tr zpt:repeat="deposit deposits"> <td zpt:insert="deposit/date">01/02/2001</td> <td zpt:insert="deposit/amount">23.40</td> </tr> </table> This is not only valid XHTML, but (borrowing an idea from Enhydra's XMLC template scheme) the ZPT template scheme allows prototypical content to be used as a proxy for the data to be substituted, so making it easier to work with in an authoring tool. An overview of the ZPT project can be found at http://www.zope.org/Wikis/DevSite/Projects/ZPT/VisionStatement More information on ZPT's attribute language is at http://www.zope.org//Wikis/DevSite/Projects/ZPT/TAL Hamish Lawson * Zope is a leading open-source web application server and content-management framework; it is written in Python. ____________________________________________________________ Do You Yahoo!? Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk or your free @yahoo.ie address at http://mail.yahoo.ie