Re: [boost] [review][mp11] Formal review of Mp11

Subject: Re: [boost] [review][mp11] Formal review of Mp11
From: Peter Dimov (lists_at_[hidden])
Date: 2017-07-20 00:22:06

Brook Milligan wrote:
> > 1. Should Mp11 be accepted into Boost? Please state all conditions  for 
> > acceptance explicitly.
>
> I feel Mp11 should definitely be accepted.

Thanks Brook.

Zach Laine wrote:
> This is one of the things with which I'm struggling when considering the 
> use of mp11, or Brigand, or any of the other recent offerings out there.
>
> I've found TMP so *easy* in 11 and later, that I've entirely stop using a 
> library to do it.  I'm trying to understand why anyone would -- that's not 
> my making an argument, just failure of imagination. :)

It gets really easy in 17 and later, as you no longer need mp_all because of 
fold expressions and there are all kinds of ad-hoc primitives in the 
standard library so you can get by. So for instance if you have a pack T... 
you can check if all those types are const (toy example) by doing 
(std::is_const_v<T> && ...), instead of mp_all<std::is_const_t<T>...> or 
gathering the types into an mp_list<T...> L and then using mp_all_of<L, 
std::is_const_t>.

But even then, mp_unique or mp_remove(_if) are no fun to write by hand.

In short, if what you want to do is not a simple pack expansion, you 
probably want to use the library. That, or reimplement it. :-)