lexer/parser library for D

[Jonathan]

Are there any good lexer and parser libraries (like flex/bison) 
for D?  If not, how much work would be involved in using flex and 
bison and wrapping it to D?  How straightforward is it to pass a 
struct from C to D (the documentation 
http://dlang.org/struct.html just says that D structs go directly 
to C -- the other way holds too if the C side is written in a 
certain way, but gives no examples of what is needed on both 
sides)?