Dia ext_attribute aggregate function question

["Donato Azevedo" <donatoaz gmail com>]

Hi guys,

I am considering using dia for a project on my company but we need a
feature that I could not find described on the docs. So I am asking
here in case there is indeed a way to do it:

I want to create an extra attribute that is a function of the block's
children, for instance, I have an attribute called Cost: if a block is
a summary block (meaning it is composed of others) the value of Cost
is the sum of the attribute Cost of its children.

        _________________
        |Summary Block  |
        |               |
        | Cost=2        |
        -----------------
                /\
               /  \
              /    \
        _____v__  __v_____
        | Leaf |  | Leaf |
        |cost=1|  |cost=1|
        --------  --------

Is it possible with Dia? Or would it require a developing effort?

Thank you very much for the attention.

Donato Azevedo
BSEng. Ctrl & Automation - UFMG - 10o per.
"Try not. Do or do not. There is no try."
 -- Master Yoda