This might be OK for someone using your files (a bit like a header-only library) but not so great for team development.
You still organize the big file into sections to keep things together that are semantically related. For Git it mostly doesn't matter whether it's 100 small files or a single big one.
I believe that's called a unity build. Really nice speedup.
SQLite calls this an "amalgamation". It is easy and convenient for users (not developers) of SQLite code.
- Single translation unit (main.cpp)
- Include all other cpp files in main
- Include files in dependency order (no forward declarations)
- No circular dependencies between files
- Each file has its own namespace (e.g. namespace draw in draw.cpp)
This works well for small to medium sized projects (on the order of 10k lines). I suspect it will scale to 100k-1M line projects as long as there is minimal use of features that kill compile times (e.g. templates).