AST files instead of DI interface files for faster compilation and easier distribution

[Walter Bright]

On 6/14/2012 11:58 PM, Don Clugston wrote:
> And we're well set up for parallel compilation. There's no shortage of things we
> can do to improve compilation time.

The language is carefully designed, so that at least in theory all the passes 
could be done in parallel. I've got the file reads in parallel, but I'd love to 
have the lexing, parsing, semantic, optimization, and code gen all done in 
parallel. Wouldn't that be awesome!

> Using di files for speed seems a bit like jettisoning the cargo to keep the ship
> afloat. It works but you only do it when you've got no other options.

.di files don't make a whole lotta sense for small files, but the bigger they 
get, the more they are useful. D needs to be scalable to enormous project sizes.