Re: [boost] review request: addition to type_traits library of is_less_comparable<T, U> and others

Subject: Re: [boost] review request: addition to type_traits library of is_less_comparable<T, U> and others
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2009-10-09 19:27:56

AMDG

Stewart, Robert wrote:
> Frédéric Bron wrote:
>   
>>> what about:
>>> is_less_than_comparable and has_operator_less_than
>>> first check for existance and bool compliance, second check
>>> for existence only
>>>       
>> Sounds very good to me.
>> has_operator_less_than or has_less_than_operator?
>>     
>
> I agree that splitting those is useful.  has_operator_less_than is more consistent with C++ syntax: operator <.
>
> If we (can) add functionality to deduce the operator's return type, then I think you'd need something like result_of_operator_less_than<T,U>::type.  Given that, one can check it against void, bool, tribool, or anything else of interest.
>   

It's easier to test the result of operator< (for example to determine
whether it is convertible to bool than it is to deduce the return type.)

In Christ,
Steven Watanabe