[Zope] temporary images

[Robin Becker]

In article <dBxWjBAissu3EwWl@jessikat.demon.co.uk>, Robin Becker
<robin@jessikat.demon.co.uk> writes
>My Zen has vanished. I want to calculate some images and have them
>displayed. I tried some simple experiments with external methods.
>
>ImageClock(self) computes the bytes for a Gif image of the current time.
>UniqueId(self) returns a unique identifier. ChartClock is defined thusly
>def ChartClock(self):
>    return self.REQUEST['ChartClock']
>
>when this is displayed I see the first image, but not the second.
>
><dtml-var standard_html_header>
><p>This works <img src=ImageClock?_,<dtml-var UniqueId> ></p>
><dtml-call "REQUEST.set('ChartClock',ImageClock(_))">
><p>This doesn't <img src=ChartClock?_,<dtml-var UniqueId> ></p>
><dtml-var standard_html_footer>
>
>Firstly why don't I get an error with too many arguments.
>Secondly why/how do these two processes differ.
>
>The reason for the <dtml-var UniqueId> is to make each view of the clock
>different.
I found that ChartClock should be defined as
def ChartClock(self):
    return self['REQUEST'].ChartClock

unfortunately this just raises the question as to why I didn't get an
error message with the former. I still don't see the second image.
-- 
Robin Becker