Subject: Re: [boost] RE [Boost-announce] [Review] Boost.Type Traits Extension by Frederic Bron
From: vijayan (vijayan121_at_[hidden])
Date: 2011-03-15 05:38:14
> Why? is it to avoid confusion with "equal to"?
> I like plus_equal because plus is a sign and equal is also a sign too. So
> I think it is easier to remember.
I also tend to vocalize += as 'plus equal'.
I suggested plus_assign because of the assign member function
provided by standard containers.
> This is not related to the return type. Only to the arguments of the operator.
Oh, I see.
> I think it is best to have the default behavior to forget about the
> return type. Why would you impose return type to be LHS?
> It is fine for +, -, ... when RHS=LHS but when you start to deal with
> different types, I think it just adds confusion.
I see your point.
And there is also an issue with derived class to base class conversion,
where the base class may have overloaded an operator.
> has_operator_plus<double, int> would then check for a return type
> "double" while has_operator_plus<int, double> for a return type int.
> You would break the symmetry of these operators.
> Also what about dereference operator?
Yes, it has been a perennial issue. Like in std::max<int,double>.
Unfortunately there doesn't seem to be a universally satisfying solution.
Fortunately, it is not a first order issue; one can always refuse to use
the default for the result type.
Thanks and regards
Vijayan