Logical const

[Peter Alexander]

On 29/11/10 3:19 PM, so wrote:
> Second why do mark something const if it is not, this is a wrong
> approach even in C++ which provides explicit "mutable".

It is logical const. It is the correct approach in C++.

> How are you going to do caching anyways, if static array is not the case?
>
> struct matrix {
> f32[4][4] m;
> f32 det_cache; // ?
> f32 mag_cache; // ?
> f32 whatever_cache; // ?
> };
>

I described the mechanisms of this in the original post. You have a 
'is_dirty' member function, which is marked as true if you modify the 
matrix. The getDeterminant function only calculates the determinant if 
is_dirty is true, otherwise it returns the cached version.