Skip to content
New issue

Have a question about this project? # for a free GitHub account to open an issue and contact its maintainers and the community.

#

By clicking “#”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? # to your account

Implement Extend trait #142

Open
wants to merge 2 commits into
base: master
Choose a base branch
from
+15 −0
Open

Implement Extend trait #142

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
6171b1c
Implement Extend trait
SalsaGal Feb 2, 2024
bb68fb4
Replace implenting Extend for a simple function
SalsaGal Feb 2, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 8 additions & 0 deletions src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1200,6 +1200,14 @@ impl<T> Slab<T> {
}
}

impl<T> Extend<T> for Slab<T> {
fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
for value in iter.into_iter() {
self.insert(value);
}
}
}
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Inserting values into a slab without saving the resulting indexes is usually not useful. Do you have a use-case for this?

Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I was thinking about that, I personally have a use case where the resulting indices aren't used, but it might be good to not use the trait at all and just have a function that returns Vec<usize> or an iterator like that instead?

Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Something like this might work:

pub fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) -> Vec<usize> {
    iter.into_iter().map(|x| self.insert(x)).collect()
}

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Actually, I think I prefer the original version. A Vec<usize> will often not be the form that the user wants the indexes in.

I think it's okay to just say that users who want the indexes can iterate it themselves.

Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

What about -> impl Iterator<Item=usize>?

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

That could make sense, but it would be a larger change. I don't think we can do it without a custom iterator.

Not having a return value allows us to follow the existing trait.


impl<T> ops::Index<usize> for Slab<T> {
type Output = T;

Expand Down
8 changes: 8 additions & 0 deletions tests/slab.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,14 @@ fn insert_with_vacant_entry() {
assert_eq!(123, slab[key]);
}

#[test]
fn extend() {
let mut slab = Slab::with_capacity(5);
slab.extend(1..9);
assert_eq!(slab[5], 6);
assert_eq!(slab.len(), 8);
}

#[test]
fn get_vacant_entry_without_using() {
let mut slab = Slab::<usize>::with_capacity(1);
Expand Down