"Daniel James" <daniel@calamity.org.uk> wrote in message news:d1nff6$ph6$1@sea.gmane.org... Thorsten Ottosen wrote:
that Joachin don't like the idea is ok, it's just not an arguemnt in favor of much.
I was just recapping what conversation there was. But it does make three people opposed to the idea.
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all decision should, if possible, be based on arguments not on personal opinions
What are the obstacles? The unordered containers can define their own version.
But there could be other containers which also cause problems which we can't anticipate. Or other types which have a sequence, but don't define equality in terms of that sequence.
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The rule of thumb is that you must make sure objects comparing equal has the same hash-value; what the hash-value is is not a problem AFAICT.
Btw, would you please describe why the unordered containers would "break"?
It's possible for two unordered containers to contain exactly the same elements but in a different order. So they would get different hash values for hash_range, but are considered equal (although equality isn't usually defined anyway).
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if equality isn't defined, then it makes little sense to use them as index in a hash-based container. In fact, it won't compile. -Thorsten