[Evolution-hackers] [plugin-development] Adding a new filter action (replace subject in mail)

[Mats Taraldsvik <mats taraldsvik broadpark no>]

Hi!

I'd like to make a plugin which replaces the subject (or parts of it)
with text from the mail contents by regular expressions. 

Rationale: Forums and others send you messages with subject like "new
reply in forum", but the topic is not specified. This is annoying if you
have one email per response, since you have to look through all this
mail to see if other topics you are subscribed to has unread responses.

As I have no earlier experience in contributing, I'd like some help on
where to start, please. I have looked in the Eplugins doc, but couldn't
figure out filter actions.

cheers,
Mats Taraldsvik

(this was also posted on evolution-list, but I was advised to post here)