[boost] Re: Policy or Trait?

From: Robert Bell (belvis_at_[hidden])
Date: 2004-04-02 13:43:37

Gennadiy Rozental wrote:
>>There's nothing wrong with that.  It is std::basic_string's
>>interface that provides for the use of a policy class.  That
>>std::char_traits happens to be the most appropriate -- it rarely
>>isn't -- implementation of that policy is beside the point.  You
>>can argue that std::basic_string shouldn't have such a policy
>>parameter, and you'd probably be right, but that's not
>>std::char_traits' fault.
> 
> 
> That's right. It's basic_string fault, which should've used char_traits by
> name in basic_string implementation.

I don't want to turn this into a std::string discussion, but if 
basic_string used char_traits by name, how would you define two 
different string types using char*, one with case-sensitive comparison 
and one without? With basic_string the way it is, it's possible; the way 
you're proposing, I don't see how to do it.

There are lots of problems with basic_string, but

template<typename T, typename traits = xxx<T> >
class foo;

isn't one of them.

Bob