[Zope-dev] Setting vars in expression eval() namespace

[Julio Maia]

Hi,

I'm trying to create a tag to evaluate the expression passed to it, adding in the expression eval namespace a variable that contains the result of dtml processing of the tag's block. For instance, the following construct:

<dtml-bvar "foo(a=1)" var="block">
   some text <dtml-var "1+2">
</dtml-bvar>

would invoke the expression "foo(a=1)" with a variable named 'block' set to 'some text 3' in the expression's namespace (btw, is it possible to achieve this using regular dtml?).

However, I couldn't find a way to set a variable in the namespace used in the evaluation of the expression. I've tried to insert an entry in the mappings passed to the expression eval() method as follows:

def __init__(self, blocks):
   tname, args, section = blocks[0]
   self.section = section.blocks
   ...
   # code that sets self.blockvar as the "var" attribute
   # code that sets self.expr as the tag's expression

def render(self, md):
   ...
   d[self.blockvar] = render_blocks(self.section,md)  # process the dtml block
   d={}; md._push(d)
   e = Eval(self.expr, expr_globals).eval(md)
   return render_blocks([e],md)

But this doesn't seem to do it.

Any hints on how to make this work?

Julio