add Option::{zip,zip_with} methods under "option_zip" gate by WaffleLapkin · Pull Request #69997 · rust-lang/rust (original) (raw)
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Edit: Tracking issue
This PR introduces 2 methods - Option::zip and Option::zip_with with
respective signatures:
- zip:
(Option<T>, Option<U>) -> Option<(T, U)> - zip_with:
(Option<T>, Option<U>, (T, U) -> R) -> Option<R>
Both are under the feature gate "option_zip".
I'm not sure about the name "zip", maybe we can find a better name for this.
(I would prefer union for example, but this is a keyword :( )
Recently in a russian rust begginers telegram chat a newbie asked (translated):
Are there any methods for these conversions:
(Option<A>, Option<B>) -> Option<(A, B)>Vec<Option<T>> -> Option<Vec<T>>?
While second (2.) is clearly vec.into_iter().collect::<Option<Vec<_>>(), the
first one isn't that clear.
I couldn't find anything similar in the core and I've come to this solution:
let tuple: (Option, Option) = ...; let res: Option<(A, B)> = tuple.0.and_then(|a| tuple.1.map(|b| (a, b)));
However this solution isn't "nice" (same for just match/if let), so I thought
that this functionality should be in core.
(rust_highfive has picked a reviewer for you, use r? to override)
I'm not sure about the name "zip", maybe we can find a better name for this.
zip is clearly the right name as it is analogous to Iterator::zip. (We don't have Iterator::zip_with though.)
Other currently possible solutions:
let tuple: (Option, Option) = ...; let res: Option<(A, B)> = match tuple { (Some(a), Some(b)) => Some((a, b)), _ => None, };
#![feature(try_blocks)] // require nightly let tuple: (Option, Option) = ...; let res: Option<(A, B)> = try { (tuple.0?, tuple.1?) }
We don't have Iterator::zip_with though
Hmmm, a.zip_with(b, |x, y| ...) is the same as a.zip(b).map(|(x, y)| ...)
I'm in favor of adding Option::zip at least by analogy to Iterator::zip (see also Option::flatten which was also accepted by analogy to Iterator::flatten). Also, I believe Option::zip to be a useful and fairly common operation to justify its addition on its own merits (as opposed to a precedent based justification).
I'm less sure about zip_with though, as it does not have similar precedent.
☔ The latest upstream changes (presumably #70062) made this pull request unmergeable. Please resolve the merge conflicts.
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Thanks a bunch for the PR!
I agree with @Centril and am also in favor of adding Option::zip. I think I'd prefer not to add Option::zip_with though. I think it's pretty niche. But I'm fine with merging it as unstable to find out if users find good uses for it.
I added a few line comments, but nothing serious. And you need to rebase.
This commit introduces 2 methods - Option::zip and Option::zip_with with
respective signatures:
- zip:
(Option<T>, Option<U>) -> Option<(T, U)> - zip_with:
(Option<T>, Option<U>, (T, U) -> R) -> Option<R>Both are under the feature gate "option_zip".
I'm not sure about the name "zip", maybe we can find a better name for this.
(I would prefer union for example, but this is a keyword :( )
Recently in a russian rust begginers telegram chat a newbie asked (translated):
Are there any methods for these conversions:
(Option<A>, Option<B>) -> Option<(A, B)>Vec<Option<T>> -> Option<Vec<T>>?
While second (2.) is clearly vec.into_iter().collect::<Option<Vec<_>>(), the
first one isn't that clear.
I couldn't find anything similar in the core and I've come to this solution:
let tuple: (Option<A>, Option<B>) = ...;
let res: Option<(A, B)> = tuple.0.and_then(|a| tuple.1.map(|b| (a, b)));However this solution isn't "nice" (same for just match/if let), so I thought
that this functionality should be in core.
If Option::zip_with addition is so questionable, shouldn't we use a different gate for it ("option_zip_with")?
- remove
#[inline]attributes (see rust-lang#69997 (comment)) - fill tracking issue in
#[unstable]attributes - slightly improve the docs
If
Option::zip_withaddition is so questionable, shouldn't we use a different gate for it ("option_zip_with")?
I don't have a strong preference, but I'd say you can keep it as is for now. I suspect that when we are discussing stabilizing zip, we will either also stabilize zip_with or remove it completely. I doubt we would be keeping it as unstable.
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Just a tiny thing still.
📌 Commit 121bffc has been approved by LukasKalbertodt
Status: Waiting on bors to run and complete tests. Bors will change the label on completion.
and removed S-waiting-on-review
Status: Awaiting review from the assignee but also interested parties.
labels
Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this pull request
…bertodt
add Option::{zip,zip_with} methods under "option_zip" gate
This PR introduces 2 methods - Option::zip and Option::zip_with with
respective signatures:
- zip:
(Option<T>, Option<U>) -> Option<(T, U)> - zip_with:
(Option<T>, Option<U>, (T, U) -> R) -> Option<R>Both are under the feature gate "option_zip".
I'm not sure about the name "zip", maybe we can find a better name for this.
(I would prefer union for example, but this is a keyword :( )
Recently in a russian rust begginers telegram chat a newbie asked (translated):
Are there any methods for these conversions:
(Option<A>, Option<B>) -> Option<(A, B)>Vec<Option<T>> -> Option<Vec<T>>?
While second (2.) is clearly vec.into_iter().collect::<Option<Vec<_>>(), the
first one isn't that clear.
I couldn't find anything similar in the core and I've come to this solution:
let tuple: (Option<A>, Option<B>) = ...;
let res: Option<(A, B)> = tuple.0.and_then(|a| tuple.1.map(|b| (a, b)));However this solution isn't "nice" (same for just match/if let), so I thought
that this functionality should be in core.
Centril added a commit to Centril/rust that referenced this pull request
…bertodt
add Option::{zip,zip_with} methods under "option_zip" gate
This PR introduces 2 methods - Option::zip and Option::zip_with with
respective signatures:
- zip:
(Option<T>, Option<U>) -> Option<(T, U)> - zip_with:
(Option<T>, Option<U>, (T, U) -> R) -> Option<R>Both are under the feature gate "option_zip".
I'm not sure about the name "zip", maybe we can find a better name for this.
(I would prefer union for example, but this is a keyword :( )
Recently in a russian rust begginers telegram chat a newbie asked (translated):
Are there any methods for these conversions:
(Option<A>, Option<B>) -> Option<(A, B)>Vec<Option<T>> -> Option<Vec<T>>?
While second (2.) is clearly vec.into_iter().collect::<Option<Vec<_>>(), the
first one isn't that clear.
I couldn't find anything similar in the core and I've come to this solution:
let tuple: (Option<A>, Option<B>) = ...;
let res: Option<(A, B)> = tuple.0.and_then(|a| tuple.1.map(|b| (a, b)));However this solution isn't "nice" (same for just match/if let), so I thought
that this functionality should be in core.
bors added a commit to rust-lang-ci/rust that referenced this pull request
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Status: Waiting on bors to run and complete tests. Bors will change the label on completion.