Re: [boost] "Simple C++11 metaprogramming"

Subject: Re: [boost] "Simple C++11 metaprogramming"
From: Peter Dimov (lists_at_[hidden])
Date: 2015-07-16 07:12:42

Mathias Gaunard wrote:
> A core foundational library should not instantiate templates that it 
> doesn't strictly need to.
> Instantiating templates has a very high impact on compile-time memory 
> usage, performance, ...

That's not always true in C++11/17. One example is the and<T...> primitive, 
for which the short-circuit version is much slower than the one that always 
expands T::value... . Another is find_if<L<T...>, P>, which is also much 
faster when it expands P<T>... for every element, even though it technically 
doesn't need to proceed beyond the first element for which P<T> is true.

> and on the well-formed programs it allows.