Re: [boost] RE [Boost-announce] [Review] Boost.Type Traits Extension by Frederic Bron

Subject: Re: [boost] RE [Boost-announce] [Review] Boost.Type Traits Extension by Frederic Bron
From: Vicente Botet (vicente.botet_at_[hidden])
Date: 2011-03-15 06:00:07

Frédéric Bron wrote:
> 
> 
>> For example:
>> has_operator_unary_minus < class RHS, class RET=RHS >
>> has_operator_minus_assign < class LHS, class RHS=LHS, class RET=LHS >
>> This would take care of most of the normal use cases.
> 
> 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.
> has_operator_plus&lt;double, int&gt; would then check for a return type
> "double" while has_operator_plus&lt;int, double&gt; for a return type int.
> You would break the symmetry of these operators.
> 

User wanting symmetry could use common_type&lt;LHS,RHS&gt; in this case. But
using it as default is not good idea as common_type is not always defined.
So I agree to change the default behavior to don't check.

Best,
Vicente

--
View this message in context: http://boost.2283326.n4.nabble.com/RE-Boost-announce-Review-Boost-Type-Traits-Extension-by-Frederic-Bron-tp3353554p3356111.html
Sent from the Boost - Dev mailing list archive at Nabble.com.