Lenses in Rust and My Solution
21 points by LambdaLemon
21 points by LambdaLemon
This is a fairly nice API, especially compared to the examples you show, but the part I'm still confused about is how a self: &Optics<'_, Foo> allows for mutation of self.y. It is behind a shared reference, so any mutation seems about as safe as mutation of a RefCell. That is, it needs to be checked by hand & at runtime instead of being enforced by the type system.
Looking at your code, this is indeed the case: there are panic!("gulp") cases to handle invalid borrows. Do you know if the other lens crates have this same failure mode?
The example pseudo-code isn't meant to be an example on how to use my library, just something to show people who are unfamiliar with lenses in general how they work. Maybe I should make a note about this.
Looking at your code, this is indeed the case: there are panic!("gulp") cases to handle invalid borrows. Do you know if the other lens crates have this same failure mode?
I have no idea to be honest. I just spent 30 minutes trying to figure out what lens-rs is doing but the code is very obtuse.
wow ur the coolest ur so good at rust lemon this is so crazy no way im literally crying
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