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Subject: Re: [boost] [Review] TTI
From: Jeffrey Lee Hellrung, Jr. (jeffrey.hellrung_at_[hidden])
Date: 2011-07-26 17:58:03

On Tue, Jul 26, 2011 at 2:25 PM, Edward Diener <eldiener_at_[hidden]>wrote:

> On 7/26/2011 5:03 PM, Jeffrey Lee Hellrung, Jr. wrote:
>> On Tue, Jul 26, 2011 at 1:19 PM, Noah Roberts<roberts.noah_at_[hidden]**
>> >wrote:
>> [...]
>> One thing that I think is missing is the option to check for a named
>>> callable within a type. For example, one might want to use enable_if
>>> style
>>> concept checking. So long as a type has function 'xxx' that takes
>>> arguments
>>> of type x,y,and z, and returns something convertible to type A, the
>>> concept
>>> is obeyed. I don't believe this can be done with C++03, but with C++1X I
>>> was able to do something using decltype.
>>> [...]
>> Actually, you can approximate it pretty well in C++03 (using derivation
>> and
>> using tricks) to the point that I think it will work pretty much as you
>> expect except for nullary member functions, where your queries must be
>> more
>> restrictive. This is a useful query, but I believe Edward has decided it
>> to
>> be outside the scope of TTI.
> I am not sure what the OP means by 'named callable". If it can be
> introspected within the type I can consider whether it can be done or not.

I think you missed the convertibility requirement(s).

This is something more along the lines of Frederic Bron's Type Traits
Extension, I think.

- Jeff

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