const - Best practices

[Rob]

"Peter Alexander" <peter.alexander.au at gmail.com> wrote in message 
news:ifl719$2hph$1 at digitalmars.com...
> Ok, so while I'm still not 100% satisfied with the lack of logical 
> const in D, I'm willing to see how far I can get without bitwise const 
> without going crazy, and I just want to clarify some things.
>
> Andrei has commented a couple of times on the fact that D's const has 
> more guarantees than C++'s const, and as a result you should use it a 
> lot less often than you do in C++.
>
> Questions:
>
> 1. What exactly does this mean? What are the situations where you 
> should use const in C++, but not in D?
>
> 2. When designing base classes and interfaces, when should you mark a 
> member function as const? In C++ you would do so for any accessor, as 
> they would be logically const. In D, you can't assume that an accessor 
> is bitwise const (due to lazy initialisation and caching), so when do 
> you make it const in the base class, and when do you leave it mutable?
>
> 3. When should you take const references in template functions 
> (essentially same subquestions as above).
>
> Final note: my intention here is not to start another logical const vs. 
> bitwise const war. I just want to know how the differences in const 
> from C++ affect library design, and what the best practices for 
> const-correctness are in D.
>

What he said, and a matrix of when to use const vs. mutable and vice 
versa please.