[Zope] DTML equiv of eval (again).

[Evan Simpson]

chas wrote:

> Just when I thought I understood how to use _['var' + x] as
> an equivalent of eval() within DTML, this one trips me up :
>

[snip]

> But this does not :
> <dtml-var "_['Images.img' +  x]">

This would find a single object which has Id ('Images.img'+x).  In fact,
one of the primary reasons for using _[''] notation in expressions is to
allow references to Ids with periods and other characters in them which
are not legal in Python identifiers.  _[] is not like eval(), it's a
simple namespace lookup.  The DTML equivalent of eval() is <dtml-var
expr="expression"> (no, I'm not kidding!)

In your case, you want either <dtml-with Images><dtml-var
"_['img'+x]"></dtml-with>, or my unreleased Product which allows
expressions like <dtml-var "_['Images/img'+x]">.