I looked into modding the Source source code and damn... that's a lot of setup required. Here I was, thinking "can't be that hard to add 20 lines of code" and whatchaknow turns out it'd be like 99% setting up the IDE and 1% coding. Lol. Anyway, all tutorials I've seen refer to Visual Studio, now I'm wondering whether the process is easier/harder/considerably different with other IDEs (or without an IDE at all)? As in, writing the code in a regular text editor and compiling it from terminal.
You can compile the Visual Studio solution (generated by Valve Project Creator) through the command-line using MSBuild. Using another IDE is possible if 1) it can use VS 2013 build tools and 2) it can import/open/parse VS solution and projects. For example: using VS 2019 with VS 2013 build tools is possible (requires both VS 2013 and VS 2019 to be installed). CLion requires you to ditch VPC for CMake.