why use special config formats?

[Joel Hedlund]

I agree with Steve and I agree Sybren. 

Also:
This is a Bad Idea, since you should never add more complexity than needed. Imports, computation, IO and so on are generally not needed for program configuration, so standard configfile syntax should therefore not allow it. Otherwise you may easily end up with hard-to-debug errors, or even worse - weird program behavior. 

/Joel