That is the context of the first sentence in your comment, pretty much the only part I left alone. Everything I replied to is the opinion you personally expres

That is the context of the first sentence in your comment, pretty much the only part I left alone. Everything I replied to is the opinion you personally expressed. And note that the author had already preempted your comment in the first place: > When we want a list of all the primes below some known limit, gen_primes_upto is great, and performs fairly well. There are two issues with it, though: > We have to know what the limit is ahead of time; this isn't always possible or convenient.