Subject: Re: [boost] [Variant] C++11 variadic template implementation
From: Larry Evans (cppljevans_at_[hidden])
Date: 2012-05-01 07:30:08
On 04/15/12 14:06, Larry Evans wrote:
> On 04/15/12 08:02, paul Fultz wrote:
>> ----- Original Message -----
>>> From: Mathias Gaunard <mathias.gaunard_at_[hidden]>
>>> Did you find a magic way to make a switch statement from a template
>>> parameter pack?
>> Well you can expand the parameter pack to create a static array of
>> function pointers. This is how it is done in this implementation:
> IIUC, something similar was proposed earlier; however, a preprocessor
> generated switch statement was deemed faster:
> However, maybe compiler's have improved since then.
Looking closer, I see that the gmane.comp.lib.boost.devel/169739
code did not use parameter pack expansion because it didn't use
variadic templates; however, it did use a vector of function pointers.
Also, apparently the switch library has an alternative implementation
which does something similar here:
There's also, apparently, a test driver to compare the speed of
alternative implementations here: