Re: want to pass vector<foo*> to fn expecting vector<const foo*>
In article <6t2dnURZG_3cX-7MnZ2dnUVZ8gadnZ2d@bt.com>,
francis.glassborow@btinternet.com (Francis Glassborow) wrote:
The problem is actually unrelated to issues with the safety of the
type system. The problem is with templates. These create unrelated
types. So there is no relationship in so far as the language
specification is concerned, between
std::vector<foo *> and std::vector<const foo *>
I am at a loss to see how we could specify such a relationship
without, at the same time, introducing a great gaping hole in
the type system.
As I understand it, we want the effect of something like:
vector<foo*>::operator vector<const foo *> &() const {
return *(vector<const foo*> *)this;
}
Achieving this would be a matter of using pointer_traits to turn
<T *> into <const T *> and then using enable_if to disable the
operator when T is not a non-const pointer. Am I missing something?
-- Dave Harris, Nottingham, UK.
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