[Zope] string into var/ filesize

Zopistas, I've got a download preview page for a pdf file. The pdf file is in the same directory and called pdf. In a method attached to the preview document, I want to find out the filesize of the associated pdf file. Something like this: <a href="<dtml-var absolute_url>.pdf">Download</a> XYZkb except XYZkb should be replaced with <dtml-var "pdffile.filesize()"> or something like that. But it has to generate the name for pdffile from the preview page id. So something like: <dtml-let "pdffile=id()+ 'pdf'"> <dtml-var "_[pdffile].filesize()"> This doesn't work, but I'm not sure what to do. I'm still totally confused about _. -- Ethan "mindlace" Fremen you cannot abdicate responsibility for your ideology.