A trivia nugget often recounted here on HN is that .NET's GC was originally written in Lisp, then translated to C++.
Nothing wrong with a large file. The editor should be able to help you navigate and see the file without the size being a concern at all.
:split :vsplit
That said, I never use it because everyone else complains about it.
I realized I’d made this shift a couple years ago when I had a ~500 line (god, that’s not even that long) single-file program I was very happy with and thought well-organized and someone a fair bit more junior complained that it needed to be split up just because it was long.
Ew. No. Thought a decade or more ago I might have thought the same thing.
Jetbrains's suite has a very large but reasonable limit (500k lines IIRC) before it simply disables it code analysis/highlighting. You can increase it if you need to, but I imagine they keep that number by default for perfomance reasons.
I’m honestly surprised there doesn’t have exist an editor/language that abstracts away the concept of source code files completely. I assume that there is a good chance that in 50 years time we won’t be coding using collections of text files.