CC Mode and GCC/CEDET integration for evaluating macros

[Oleh Krehel <ohwoeowho@gmail.com>]

Hi all,

I just went through the whole CC Mode manual, just to make sure that I'm
not being silly asking for an existing feature.

I'd like to be able to evaluate the current symbolic constant at point
with "C-x C-e" for C/C++.  Moreover, I remember when I was using Visual
Studio 10 years ago, it had a feature of parsing the macros and graying
out #ifdef branches. I found a screenshot of this if it's not clear what
I mean: http://stackoverflow.com/questions/11610549/

I think it would be really cool to add both these features to CC Mode.
So I'd like to ask:

1. Is there any past progress towards these features?

2. How viable is it to implement them? Could they work for the most
common build systems?

3. Could / should they be implemented based on CEDET or GCC?

4. How hard would it be to actually do it all? Are there any predictable
roadblocks?

5. Would other people besides me find these features useful?

Oleh