Vladimir Panteleev:
> Often I encounter cases where I have a function taking some arguments, and I'd like for the compiler to generate separate code for the function when some of the arguments are known at compile time.

That's named partial compilation, in this newsgroup I have discussed it a little in the past: http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=75312

Bye,
bearophile