The Snazzy D Compiler
github.com
github.com
This is pretty neat.
"Do the hard part first", isn't exactly a new or unique design idea, but it's certainly rare enough to be highlighted.
"Its intent is to provide a D compiler as a library (libd) in order to improve the overall D toolchain by enabling the possibility of developing new tools."
DMD as a library: Myths & Reality [PDF]: