Re: [boost] [functional] [overloaded_function] polymorphic functions?

Subject: Re: [boost] [functional] [overloaded_function] polymorphic functions?
From: Dave Abrahams (dave_at_[hidden])
Date: 2012-03-14 18:33:34

on Wed Mar 14 2012, Gordon Woodhull <gordon-AT-woodhull.com> wrote:

>> If the type of o did not involve poly, then you could pass a reference
>> to o to another translation unit where the definition of poly was not
>> visible.  In that other translation unit you could call it with an
>> arbitrary type, which would have to instantiate poly::operator() without
>> sight of its definition.  Therefore, I conclude that this is clearly
>> impossible.
>
> I had neglected the fact that overloaded_function does type erasure
> (duh).  I guess this would only be possible if the polymorphic
> result_of (or equivalent) is passed to overloaded_function.  Probably
> not worth it.

I think Lorenzo's assessment ("not possible") is more accurate.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com