Skip to content
New issue

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

Sign up for GitHub

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

Already on GitHub? Sign in to your account

Jump to bottom

Tracking issue for entry_and_modify #44733

Closed
mchlrhw opened this issue Sep 21, 2017 · 9 comments
Closed

Tracking issue for entry_and_modify #44733

mchlrhw opened this issue Sep 21, 2017 · 9 comments
Labels
C-tracking-issue Category: An issue tracking the progress of sth. like the implementation of an RFC T-libs-api Relevant to the library API team, which will review and decide on the PR/issue.

Comments

@mchlrhw
Copy link
Contributor

mchlrhw commented Sep 21, 2017 •
edited
Loading

Tracking issue for the and_modify method on hash map Entrys (added in #44734).
@mchlrhw mchlrhw mentioned this issue Sep 21, 2017
Merged
@mchlrhw mchlrhw changed the title Tracking issue for and_then on std::collections::hash_map::Entry Tracking issue for and_then on Entry APIs Sep 21, 2017
@mchlrhw
Copy link
Contributor Author

mchlrhw commented Sep 21, 2017 •
edited
Loading

The scope of this has changed to include the BTreeMap as well as HashMap on the advice of @kennytm.

@aidanhs aidanhs added the C-tracking-issue Category: An issue tracking the progress of sth. like the implementation of an RFC label Sep 21, 2017
@mchlrhw mchlrhw changed the title Tracking issue for and_then on Entry APIs Tracking issue for entry_and_modify Sep 26, 2017
bors added a commit that referenced this issue Oct 6, 2017
@bors
Auto merge of #44734 - mchlrhw:wip/hashmap-entry-and-then, r=BurntSushi
a8feaee 
Implement `and_modify` on `Entry`

## Motivation

`Entry`s are useful for allowing access to existing values in a map while also allowing default values to be inserted for absent keys. The existing API is similar to that of `Option`, where `or` and `or_with` can be used if the option variant is `None`.

The `Entry` API is, however, missing an equivalent of `Option`'s `and_then` method. If it were present it would be possible to modify an existing entry before calling `or_insert` without resorting to matching on the entry variant.

Tracking issue: #44733.
cuviper pushed a commit to rayon-rs/rayon-hash that referenced this issue Nov 14, 2017
@bors
Auto merge of #44734 - mchlrhw:wip/hashmap-entry-and-then, r=BurntSushi
eea5bba 
Implement `and_modify` on `Entry`

## Motivation

`Entry`s are useful for allowing access to existing values in a map while also allowing default values to be inserted for absent keys. The existing API is similar to that of `Option`, where `or` and `or_with` can be used if the option variant is `None`.

The `Entry` API is, however, missing an equivalent of `Option`'s `and_then` method. If it were present it would be possible to modify an existing entry before calling `or_insert` without resorting to matching on the entry variant.

Tracking issue: rust-lang/rust#44733.
@hedgehog1024
Copy link
Contributor

hedgehog1024 commented Jan 17, 2018 •
edited
Loading

Just wonder, is there any particular reason to keep this feature unstable? I personally find it pretty usable and convenient and it doesn't look like something that can break an unspoken invariant

@kennytm
Copy link
Member

kennytm commented Jan 17, 2018

@hedgehog1024 The only reason these are kept unstable is because no one pushed for stabilization. Everyone is welcome to submit a PR to stabilize a library feature 😊.

  1. Ensure the documentations, examples and implementations are correct. Ensure no missing edge cases. Ensure necessary tests are present.
  2. Change all #[unstable] attributes related to that feature to #[stable].
  3. Submit the PR.
  4. Wait for team consensus.
  5. Profit!

@kennytm kennytm added the T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. label Jan 17, 2018
@hedgehog1024
Copy link
Contributor

@kennytm Does such a PR need to remove the information about this feature from Unstable Book?

@kennytm
Copy link
Member

kennytm commented Jan 17, 2018

@hedgehog1024 Yes. Those information should be moved into the documentation of the functions.

@mchlrhw
Copy link
Contributor Author

mchlrhw commented Jan 18, 2018

@hedgehog1024 Thanks for your support of this feature, much appreciated 😄

@hedgehog1024 hedgehog1024 mentioned this issue Feb 12, 2018
Merged
kennytm added a commit to kennytm/rust that referenced this issue Feb 25, 2018
@kennytm
Rollup merge of rust-lang#48166 - hedgehog1024:hedgehog1024-stabilize…
b443e57 
…-entry_and_modify, r=alexcrichton

Stabilize 'entry_and_modify' feature

Stabilize `entry_and_modify` feature introduced by rust-lang#44734.

Closes rust-lang#44733
@Jarngreipr
Copy link

I see this feature has been stabilised.
Should it now be available for use on stable?

I get the following error on rustc 1.25:

error[E0658]: use of unstable library feature 'entry_and_modify' (see issue #44733)
   --> src/models/mod.rs:155:34
    |
155 |                                 .and_modify(|&mut tup| {tup.1 = idx}) ;
    |                                  ^^^^^^^^^^

@mchlrhw
Copy link
Contributor Author

mchlrhw commented Apr 28, 2018

I think it's due in 1.27

@mchlrhw
Copy link
Contributor Author

mchlrhw commented Apr 28, 2018

Scratch that. I just looked on the stabilisation PR and it's slated for 1.26. Even better! 😁

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
C-tracking-issue Category: An issue tracking the progress of sth. like the implementation of an RFC T-libs-api Relevant to the library API team, which will review and decide on the PR/issue.
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
5 participants
@kennytm @aidanhs @mchlrhw @Jarngreipr @hedgehog1024