First reaction:
"Header only - This is great!"
Then I read:
"Dependencies boost".
OK, moving on...
Honest question from someone who hasn't done C++ in a very long time: why is "header only" a good thing?
>Why single-file headers?
>Windows doesn't have standard directories where libraries live. That makes deploying libraries in Windows a lot more painful than open source developers on Unix-derivates generally realize. (It also makes library dependencies a lot worse in Windows.)
>There's also a common problem in Windows where a library was built against a different version of the runtime library, which causes link conflicts and confusion. Shipping the libs as headers means you normally just compile them straight into your project without making libraries, thus sidestepping that problem.
>Making them a single file makes it very easy to just drop them into a project that needs them. (Of course you can still put them in a proper shared library tree if you want.)
>Why not two files, one a header and one an implementation? The difference between 10 files and 9 files is not a big deal, but the difference between 2 files and 1 file is a big deal. You don't need to zip or tar the files up, you don't have to remember to attach two files, etc.