Using DIA for block simulation

[Bruno Barberi Gnecco <brunobg lsi usp br>]

Hello,

        I'm writing a program that will simulate designs using blocks, something
in the lines of Matlab's Simulink or PSpice, but for a specific purpose. As the
simulator itself will require a lot of work, I was wondering if I could somehow
use Dia as a sort of GUI. I don't require much of the GUI: in fact, all I want
is a graphical tool to connect the blocks. I'd then convert it to a format of
my own and simulate it --- pretty much what spice GUIs do. 
        Anyway, my question is: is it doable? What I need is someway to create
new blocks in the GUI. They need to have input and output nodes (connection 
points), and the user must be able to select the number and name of these nodes.
The UML shapes are pretty close to what I need, except for the input/output nodes.
        I'd appreciate any thoughts or ideas. I'm willing to write support for
nodes for Dia if necessary (as question 17 of the FAQ apparently says that
I'll have to).
        Best regards,

-- 
Bruno Barberi Gnecco <brunobg lsi usp br>
http://www.lsi.usp.br/~brunobg/
   That's the difference between me and the rest of the world! Happiness isn't
good enough for me! I demand euphoria!  -- Calvin