* better syntax for optional positional arguments:
void fun(int x, [int y, int z=3]){...}
Thinking of which, this would actually solve a long standing problem in D, that
of specifying optional parameters AFTER a variadic template:
void fun(T...)(T args, [string file=__FILE__,int line=__LINE__]){...}

Not sure what that is.

* export for libraries

What does that mean?