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From: Daniel James (daniel_at_[hidden])
Date: 2005-03-22 13:41:24
Thorsten Ottosen wrote:
> Even so, does the extreamely rare situation, that a hash-container is used as
> index in a hash-container,
> justify that we should not use a generic default ?
But that was just a specific example of a general point - that we can't
define a hash function for an object when we don't know what its
equality function is.
Another example:
struct foo
{
int identity_;
std::vector<int> values_;
std::vector<int>::const_iterator begin() const {
return values_.begin();
}
std::vector<int>::const_iterator end() {
return values_.end();
}
friend bool operator==(foo const& x) const {
return identity_ == x.identity_;
}
// ...
};
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