D Compiler as a Library

[Trass3r]

> I think we've got the lexer and parser completely separate from
> most of the rest of the codebase (like the codegen), due to
> repeated requests from people who wanted to use these parts for
> IDEs and other tools.

Still some things to learn from Clang though.
e.g. it still directly builds an AST instead of using some kind of  
interface.

btw, why do you use exceptions for compiler errors instead of a cheaper  
and more sophisticated system?

> I've yet to see anyone actually go through with using it though,
> possibly because there is no documentation for a lot of it.

Yep, no comments anywhere :/