[kllrnohj]

> Because that way you don't need to haul in dependencies unless you have a real reason.

These are all largely header libraries. You're already hauling in a dependency, and in every c++ file that uses it at that.

> std::function is fine for prototyping

std::function isn't part of the containers library of the STL (containers being all the stuff here: https://en.cppreference.com/w/cpp/container ). I agree std::function is fine, it even has a pretty reasonable small-size optimization.

[mbeex]

> These are all largely header libraries.

That's not even true for boost, no matter if they always advertise that. The lib is also notorious for bad decomposability (using only a subset without installing the whole monster). Not to speak about idiosyncratic naming and build system, making it sometimes hard to include it in meta builds of other libraries and frameworks.

In sum: Anyone sensible, regarding different kinds of footprint and dependencies will think twice, before pulling in these kind of libraries.

[gpderetta]

boost does not advertise being an header only library. Some boost libraries are header only, some offer hybrid modes, some require a library to be linked in. Each case is documented individually.

Boost is better thought as a loose collection of libraries that try to follow some common design principles instead of a single monolithic library.

I can't defend the build system though.