[vtk-developers] Const correctness for string methods

[Sebastien BARRE]

At 1/19/2004 10:36 AM, David Thompson wrote:
> > I don't think you can overload based on return value.
>You cannot, but the const-ness of the member function CAN be overloaded.
>For instance,
>
>         double* GetPoint( vtkIdType );
>         const double* GetPoint( vtkIdType ) const;

Const-correctness is a non-trivial topic in VTK: it's not that easy to 
really tell if a method should be const-correct or not depending on what is 
changed internally (for example). You could call a Get() method that  looks 
like a nice const-correct candidate, but have that Get() method trigger 
another method that legitimately modifies attributes internally to perform 
a computation (for example, bounds). Worst, you could have a chain of 
methods that are all const-correct, but one day you change one call in the 
final method, and that call has to be non-const, and then it breaks havoc 
all along the chain. If I remember that behaviour can be handled through 
'mutable' attributes (Brad), but I'm not sure we want to go that way...