Scalar is implemented in C and interacts with Git via a mix of child process
invocations of Git and direct usage of libgit.a. Internally, it is structured
much like other built-ins with subcommands (e.g., git stash), containing a
cmd_<subcommand>() function for each subcommand, routed through a cmd_main()
function. Most options are unique to each subcommand, with scalar respecting
some "global" git options (e.g., -c and -C).
Because scalar is not invoked as a Git subcommand (like git scalar), it is
built and installed as its own executable in the bin/ directory, alongside
git, git-gui, etc.