pragmas for expressions?

[mgen]

> The use case you provided: Disgusting, offensive, makes me want to find 
> you and break your fingers. Compilation is a NON-INTERACTIVE PROCESS. 
> Repeat that to yourself.
> 
>   - Gregor Richards

Compilation may be non-interactive in your mind but I see it as being similair to build scripting when you do CTFE or some kind of computation. Having the option to do interesting things such as check and correct things instead of completely rebuilding does not seem like something that should just be thrown away because of your ideals that compilation is done without any interaction. Other uses could be a pragma for JiT eval of complex functions to return the structures of a parser without resulting to struct hacks which are a horrible idea. I see this as a logical step to integrate tools into compilation instead of having 2 separated programs.