RFC: naming for FrontTransversal and Transversal ranges

[Rainer Deyke]

Robert Jacques wrote:
> On Thu, 30 Apr 2009 17:23:19 -0400, Rainer Deyke <rainerd at eldwood.com>
> wrote:
>> It's possible to write a reference wrapper around a value type.  It's
>> also possible to write a value wrapper around a reference type.
>> However, the former is both easier and more efficient than the latter.
> 
> Yes and no. Yes, the deep copy mixin is more complex to write the first
> time, but after that it's easy to use. And second, it's just as
> efficient as the later, since the deep copy mixin generates the same
> code as a value type.

A simple deep-copy struct wrapper around a class type is horribly
inefficient compared to a direct struct type:
  - It uses an extra heap allocation per instance.
  - It uses an extra level of indirection.
  - It uses virtual function calls.
  - It allocates an extra reference to a virtual function table per
instance.

I suppose a very clever wrapper metaprogram or a really clever
optimizing compiler might eliminate some of these inefficiencies.


-- 
Rainer Deyke - rainerd at eldwood.com