Re: Adding optional<T&> find like method to associative containers in boost.

From: Ivan Matek (libbooze_at_[hidden])
Date: 2024-12-16 15:08:42

On Mon, Dec 16, 2024 at 12:41 PM Andrey Semashev via Boost <
boost_at_[hidden]> wrote:

> Adding find() overloads to containers means adding a dependency on
> boost::optional, which makes the container a more heavy dependency for
> the users. Since containers are often used as data members in classes,
> this increase in source code footprint arguably will be fairly visible
> across user's code base.
>

Did a quick experiment on my machine:
//#include <boost/optional.hpp>
#include <boost/unordered/unordered_flat_map.hpp>

int main() {
}

110k LOC after preprocessing(libstdc++)
90k   LOC after preprocessing(libc++)

#include <boost/optional.hpp>
#include <boost/unordered/unordered_flat_map.hpp>
int main() {
}

114k LOC after preprocessing(libstdc++)
94k  LOC after preprocessing(libc++)

So it seems that almost all the stuff that optional drags in is anyway
dragged in by unordered_flat_map.hpp

P.S. I know counting LOC is lame way to estimate compile speed, but it is
best one I know without finding some large codebase and trying to add
optional header to all places where unordered_flat_map is used.
On my machine compile time difference when adding optional header is tiny.

Different containers from boost might have different includes, so this may
not apply to them.