Indeed, it's a trivial lookup table problem, it's hard to come up with an easier one, so I would guess the confusion comes from lack of familiarity with bitwise operations, in which case why is the author presuming to write an article judging a certain implementation of bitwise operations impressive?
The intent of my comment is not to be mean, it's just ... there is a lot of noise on places like Hacker News and this article is part of that noise because, look, just about all compilers have had intrinsics for decades now at least, popcount is a very common one, so it's not surprising to see it turn up. It's not impressive as the title suggests, it's extremely common. And it's nothing specific about Rust because most production-quality languages do it. So both major elements of the article title are pretty much incorrect.
And it's fine not to know that when you're a beginner, I am not knocking that at all. But there's something about writing articles that then get broadcast, that give the wrong impression to other new people who are trying to learn. It's useful information that there is a popcount intrinsic in the Rust compiler, but this would be much more educational coming from someone who understands the context of all this stuff and can explain the real situation. Which may be the author of this article someday, maybe even someday very soon -- I don't wish to be inappropriately negative -- but it's not today.
I never liked going to school, and I think higher education is going to go through an existential crisis pretty soon, if it's not happening already. But one good thing about the old system is that at least there was this idea that you should work hard, and really learn the material, before you go presuming to teach people. And I think that's a very good idea. If you're inexperienced and there's a shortage of teachers and teaching needs to happen, then go for it -- but otherwise I think it is very important to keep in mind what one does and does not understand, and who understands it better, and to not presume to teach until one is in a good position to do so.
I know this goes a little bit against the current philosophy of "programming is great! Anyone can do it! Rah rah," but actually I think on closer inspection it doesn't. There's nothing wrong with participation, and community, and everyone contributing, etc. But it's important to keep an understanding of the difference between beginner contributions and advanced contributions, otherwise it seems possible to suffer a severe degradation of skill in the field over time, because how do people know what to shoot for if people of all expertise levels are teaching them and they can't tell the difference because they themselves are beginners?
FWIW, I think the story hit the front page simply because it was a positive story about Rust and a lot of people in this community reflexively upvote that sort of thing. I took your comment as well deserved criticism against the community.
The intent of my comment is not to be mean, it's just ... there is a lot of noise on places like Hacker News and this article is part of that noise because, look, just about all compilers have had intrinsics for decades now at least, popcount is a very common one, so it's not surprising to see it turn up. It's not impressive as the title suggests, it's extremely common. And it's nothing specific about Rust because most production-quality languages do it. So both major elements of the article title are pretty much incorrect.
And it's fine not to know that when you're a beginner, I am not knocking that at all. But there's something about writing articles that then get broadcast, that give the wrong impression to other new people who are trying to learn. It's useful information that there is a popcount intrinsic in the Rust compiler, but this would be much more educational coming from someone who understands the context of all this stuff and can explain the real situation. Which may be the author of this article someday, maybe even someday very soon -- I don't wish to be inappropriately negative -- but it's not today.
I never liked going to school, and I think higher education is going to go through an existential crisis pretty soon, if it's not happening already. But one good thing about the old system is that at least there was this idea that you should work hard, and really learn the material, before you go presuming to teach people. And I think that's a very good idea. If you're inexperienced and there's a shortage of teachers and teaching needs to happen, then go for it -- but otherwise I think it is very important to keep in mind what one does and does not understand, and who understands it better, and to not presume to teach until one is in a good position to do so.
I know this goes a little bit against the current philosophy of "programming is great! Anyone can do it! Rah rah," but actually I think on closer inspection it doesn't. There's nothing wrong with participation, and community, and everyone contributing, etc. But it's important to keep an understanding of the difference between beginner contributions and advanced contributions, otherwise it seems possible to suffer a severe degradation of skill in the field over time, because how do people know what to shoot for if people of all expertise levels are teaching them and they can't tell the difference because they themselves are beginners?