social.noyu.me

When I need to find a minimum time, minimum screen co-ordinate, etc, I often find myself writing Rust code like this:

if let Some(new) = new {
    current = Some(current.map(|i| i.min(new)).unwrap_or(new));
}

Is there a better way to do this? Even if it just covers the inner part (the case where new.is_some()), I’d love to know.

a friend told me about map_or, and made some other suggestions: https://twitter.com/mcpowr/status/1625080741657985025

this kind of reduction case can’t be that uncommon. I wonder if it would be a good candidate for a new function? no idea what to call it, definitely not .xor_or_zip_with() lol

neatest solution so far comes courtesy https://twitter.com/LambdaFairy/status/1625114170504118272

knowing Ord::max() does what we want for an Option, but Ord::min() doesn’t, then if we define an enum exactly like Option but with the variants in the reverse order, we get an enum for which Ord::min() will do the right thing (but Ord::max() doesn’t)

with that said… you should probably just use match (a, b) { and handle all four cases :p

@hikari sentient_rust_utils::do_the_specific_thing_i_need_done()

@elena oh I love that function, it even provides a formal proof that your code is correct and automatically uploads a paper it co-authored to arXiv

@hikari I'd go with .or_with(): It will result in Some when one or both of its operands are Some, so it's just a regular or and not an exclusive or.