byval keyword to make objects act as value types

[Craig Black]

>although adding those things and ctors/dtors to structs like you said
>would be just as good really. i got the impression that option was off
>the table though.
>should struct member functions & dtors be virtual by default?

Good question.  Here's my philosophy about virtual by default.  I am a 
performance-oriented guy, and I prefer the compiler to NOT make functions 
virtual when I don't explicitly say "virtual".  For me, virtual by default 
means I need to be more careful about overriding so something doesn't become 
virtual accidentally.

Further,  virtual by default prevents non-virtual overriding, which can be 
used for high-performance compile-time polymorphism using templates.

That said, if this happens at all, Walter would probably use virtual by 
default for consistency sake.  Oh well, I guess it's not that big a deal.

If polymorphism is added to structs, it should be optional.  I would have a 
problem if the vtable pointer was included in structs that didn't have any 
polymorphism.  It should work like C++ structs and classes, where there is 
no overhead for non-polymorphic types.

As for virtual destructors, I agree that they should be virtual by default, 
but only if a type is polymorphic.  Forgetting to make a destructor virtual 
in C++ can cause subtle and annoying bugs.  It's good that most C++ 
compilers issue warnings when a polymorphic type has a non-virtual 
destructor.  However, I would rather the compiler make it virtual for me.

-Craig