Making containers that "go both ways"

[Bill Baxter]

Hey,
Just wanted to throw this idea out for comment.
I find I can't really decide whether a container class should be a 
struct or a class.  Struct feels right if I want minimal overhead and 
something that works more like a built-in datatype.  But class feels 
right for situations where I'm less concerned about performance, and 
also offers the additional ability to extend the basic functionality via 
subclassing.

So something I did (a while back now...) was to create some containers 
in OpenMesh/D that use mixins for all their guts, and provide both 
struct and class wrappers for them.

It seems to me like that might be the "right" way to do containers in D. 
Somewhat unfortunately, because it's more complicated than just writing 
one or the other.

Thoughts?

--bb