[ Below I describe my solution to the problem which seems to me to be fairly frequent. Maybe someone is interested, maybe someone can show me better (faster, shorter) solution ] * Problem The problem: while presenting some page, I would like to automagically add links to 'previous' and 'next' page in the same directory. Say you organize a bunch of HOWTOS and you would like to let the people navigate via 'next' links - without going back go table of contents. * Idea What I really need is to calculate identifiers of 'neighbours' of my page in its container. I do have id of the current page, I can easily got list of all identifiers in the container. So I can just scan this list, find my id and read previous and next element. Transforming it into hyperlink is natural. * Code First I create the following Python Method (could be External Method as well). The method returns tuple (previous_id, next_id) substituting '' if there is no such element (we are at the start or at the end). ---------- Name: neighbours Parameters: self,myId,allIds Contents: position = 0 for x in range(0, len(allIds)): if allIds[x] == myId: position = x break else: raise 'Internal inconsistency: id ' + str(myId) + ' does not belong to list ' + str(allIds) left = '' right = '' if position > 0: left = allIds[position - 1] if position < len(allIds) - 1: right = allIds[position + 1] return (left, right) ---------- Then I add standard_html_footer DTML Method to the directory with my iterated items. I put there sth like that (of course presentation can vary, 'MyHowto' is the metatype of objects I iterate over, as you can see I call original footer after writting my navigational details): --------- <p> <dtml-let allIds="PARENTS[0].objectIds(['MyHowto'])" myId=id neigh="neighbours(myId,allIds)"> <table border="0" width="90%" align="center"><tr> <td width="33%" align="left"> <dtml-if "neigh[0] != ''"> <a href="<dtml-var "neigh[0]">">Previous</a> <dtml-else>   </dtml-if> </td> <td width="33%" align="center"> <a href="<dtml-var howto_index url>">Table of Contents</a> </td> <td width="33%" align="right"> <dtml-if "neigh[1] != ''"> <a href="<dtml-var "neigh[1]">">Next</a> <dtml-else>   </dtml-if> </td> </tr></table> </dtml-let> <dtml-with "PARENTS[1]"> <dtml-var standard_html_footer> </dtml-with> ---------- (by the way I do not know why I need 'myId=id' in <let> - but removing it and putting id on the neighbours parameters list does not work) * Unsolved problems There are two important unsolved problems: - efficiency - I perform linear scan which can be expensive if my directory contains a lot of objects (I do not know good method to solve it - I would need some help from Folder class) - order - if I need to present my objects in some order other than default, I would need to sort allIds in some way (probably I would need youse objectValues instead of objectIds) * Minor tricks The python method I wrote is generic, I use the same method for two different folders. In fact I worked around the order problem for the very simple case - presenting everything in reverse order. I just exchanged neigh[0] and neigh[1] in standard_html_footer. -- Serwis nie tylko mieszkaniowy: http://www.mk.w.pl | | You have the right to say how long each requirement will take you to | implement, and to revise estimates given experience. (Ken Beck's | Second Developer Right)