Not to mention if you didn't use libc - and think of how many loc it'd need if you wanted to implement the kernel and userspace tools too!
Thankfully, we live in a world where libraries exist and we can use them to handle the low-level details, and then we only need to care about the 500 lines of meaningful application-specific logic :D
So explain the point? In several threads recently I've seen people say "The application's line count is higher if you also count the libraries as part of the application!" - I mean yeah, sure, that's a factually correct statement, but... so what?
The point is that this app is 500 lines of C but it'd be two lines of Python:
from wayland import solution_to_the_problem
solution_to_the_problem()
In this case, wlroots is literally a library for writing a compositor.
("A small demonstration of the wlroots API" would have been a fine title for this post. Pretending it's a small amount of code is silly.)
"I made a tiny webserver using only the Linux kernel" is impressive. "I made a tiny webserver using only the Golang webserver API" is not as impressive. "I made a tiny social networking website using the Golang webserver API" is heading back towards impressive.
You don't have to be impressed, but I don't necessarily think it's disingenuous. A "small" Wayland compositor which doesn't use a library like wlroots is nigh impossible. The code for handling DRM+KMS alone is over 2000 lines of code, and that's tangental to the goal of "make a Wayland compositor". I'd compare it to saying a game written with GLFW isn't impressive because they didn't do all of the work to set up an application window.
For a toy compositor, is there any reason not to just use SDL? The DRM and KMS side of things is interesting, but doesn't help much in understanding the Wayland protocol.
I agree. It's a spectrum and my Python example is showing one extreme of obviously unimpressive. I was just trying to answer the comment I was responding to.
The line I'd draw is application logic (how the WM acts, how it reacts to user inputs, how it feels to the end user, the unique things which make it different to any other WM) vs library logic (the necessary groundwork which every WM is forced to implement in exactly the same way because of the protocol spec)
tinywl is 500 lines of application logic + 40,000 lines of library logic; compared to your example which is two lines, but doesn't include the application logic, which I think makes it an apples-to-oranges comparison.
Thankfully, we live in a world where libraries exist and we can use them to handle the low-level details, and then we only need to care about the 500 lines of meaningful application-specific logic :D