Re: [boost] Re: Review Request: FC++

From: Joel de Guzman (joel_at_[hidden])
Date: 2003-10-09 11:25:06

David Abrahams <dave_at_[hidden]> wrote:
> "Joel de Guzman" <joel_at_[hidden]> writes:
> 
>> David B. Held <dheld_at_[hidden]> wrote:
> 
>>     struct square
>>     {
>>         template <class X>
>>         struct sig { typedef X type; }
>>         template <class X>
>>         X operator()(X x) { return x * x; }
>>     };
>> 
>>>> [...]
>>>>     b. It should be called apply, because that just makes it
>>>>        cheaper and easier to use: instead of
>>>> [...]
>>> 
>>> But my understanding is that apply<> is the compile-time way
>>> to spell "operator()" for function objects.
> 
> Sort of.
> 
>>> If sig<> is really the definition of R for "R operator()", without
>>> being the result of operator(), should it really be spelled
>>> "apply<>"?  It seems to me that there is a confusion between
>>> runtime and compile time here.  The fact that apply<> works
>>> syntactically adds to the confusion.
> 
> *I'm* not confused.  I have no problem with the idea of having a
> class
> 
>   a. whose _instances_ can be used as a function which squares numbers
> 
>   b. which is itself a metafunction class that computes the instance's
>      return type based on the arguments passed

Snips...

For the record, I am not against naming it "apply". However, I am not sure 
how that will jive with Doug's uniform return type proposal. I'm sure
we do agree that there must be one and only one way to do it. 

Cheers,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net