On 7/15/2016 7:43 AM, Andrew Godfrey wrote:
One example is if you make a class that has an internal cache of something.
Updating or invalidating that cache has no logical effect on the
externally-observable state of the class. So you should be able to modify the
cache even on a 'const' object.
Yes, that's the "logical const" argument.
The trouble with it is there's no way for the compiler to detect that's what
you're doing, nor can it do any checks on it. In effect, C++ const becomes
little more than a documentation suggestion.
> This is not a bug and I've seen it have a huge
> effect on performance - probably a lot more than the const optimizations
Walter
> is talking about here.
You can do logical const in D just like in C++, and get those performance gains.
You just can't call it "const". But you can call it /*logical_const*/ and get
the same result.
