Read project version from version.hpp

[pleroux0]

Modifies CMakeLists.txt to determine the version from the version.hpp file to avoid duplication.

Some relevant discussion in #166

[uilianries]

Why not creating version.hpp by PEGTL version in CMakeLists.txt?

Reading a file and extracting the version by regex looks much complex than using the recommended cmake flow (cmake tutorial).

[coveralls]

Coverage remained the same at 100.0% when pulling 6111025 on pleroux0:master into 51dbee8 on taocpp:master.

[pleroux0]

That is also an option, but someone still has to check it into the repository. In a pure CMake project, it can reside in the build directory like generated files usually do (just as in the tutorial).

It makes sense to me having the version.hpp as the source of truth so that it can be used as pure header only library (just copy the sources).

[d-frey]

I like this patch as it seems "simple" and straight-forward to me.

• version.hpp is the single source of truth.
• If someone uses CMake, CMakeLists.txt takes the version from the above file.
• If someone does not use CMake, it still works out-of-the-box.
• No extra step (manual/automated) to sync two files.

Am I missing any downside?

[d-frey]

Why not creating version.hpp by PEGTL version in CMakeLists.txt?

Reading a file and extracting the version by regex looks much complex than using the recommended cmake flow (cmake tutorial).

The only problem with the CMake flow is that it assumes CMake is used. The PEGTL simply doesn't enforce users (even Colin and me) to use CMake. Support for CMake is nice, being forced to use it is... not so nice. Maybe I'm old-school, but as long as there is no downside to Paul's approach, I tend to merge the PR soon. :)

[uilianries]

oh, I see. I have to agree, your approach sounds better since this project doesn't require cmake.

Thank you @d-frey @pleroux0