Some thoughts on Generators and For-Loops

[finegeometer]

@PoignardAzur

Personally, I really wouldn't expect the "return" value of a for loop to be the value passed to the generator's resume argument (especially in case where it's not obvious that the object being iterated is a generator).

Honestly, I don't really see any use case where the syntax you suggest would be idiomatic or natural.

I got the idea from https://internals.rust-lang.org/t/pre-rfc-generator-integration-with-for-loops/6625/11.

But that is a fair criticism. I'll have to think of some examples before I decide whether I agree. I do think there should be some nice way to iterate over generators with return arguments, though. And a for_each combinator isn't enough, because we may want to yield in the body of the loop.

But I honestly think that the stuff about for-loops is the less-interesting part of my post. The more interesting part is the idea that there are different kinds of generators (stage 1 and stage 3), and that they are useful in different circumstances.