rust-lang / rust-lang/rfcs

Rename .remove() to .take() in most collection types

Open
#3,034 4 comments 5 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

T-libs
Dominant language
Markdown
Stars
6.6k
Forks
1.7k
Avg merge
16h 14m
Merged PRs (30d)
1

Description

This is something that threw me off years ago when I spent more time than I'd care to admit looking for a Collection::take() when it was actually named Collection::remove(), more specifically because I wanted to move an object out of a container (rather than simply remove it from the container) and I was going by what syntax I knew rust used in other places to do just that. Although it's been some years, it occurred to me to file an issue today, although I may have forgotten the exact details of what types I was dealing with at the time (given that this just gets harder the more one waits).

I would like to propose that methods returning T or Option<T> rather than bool should be named Foo::take() rather than Foo::remove(). This would apply to, among others, VecDeque::remove(), LinkedList::remove(), HashMap::remove(), HashMap::remove_entry(), btree_map::OccupiedEntry, hash_map::RawOccupiedEntryMut::remove(), hash_map::RawOccupiedEntryMut::remove_entry(), Vec::remove(), and (somewhat contentiously, but only if you don't primarily think of it as a collection) String::remove().

Reasons in favor of this change:

  1. It is semantically clearer: .take() implies both removing something from its current holder/owner ("taking" it away), and gaining ownership of said thing yourself, whereas .remove() only implies the former and doesn't actually differ (semantically/linguistically) from what we refer to as drop() in the rust world.
  2. It is more consistent. BTreeSet and HashSet already use .take() and most rust users are introduced to Option<T> before they ever use collections, where the nomenclature is .take() and not .remove(). Option<T>, std::mem, Cell, RefCell, OnceCell, SyncOnceCell all use .take() to relinquish ownership of an/the item/entry.
  3. It is not yet too late, as none of the mentioned types currently use .take() for anything, so .remove() could be deprecated without any breaking changes (unless any implement Iterator directly - which I don't think is the case - as std::iter::Iterator::take() is a thing)

Reasons against:

  1. It's a lot of churn.

Possible alternatives:

  1. Reserve .take() for all these types (i.e. make sure no future method is created with that name) both a) to prevent confusion, and b) so that rustc can automatically suggest using remove() any time someone mistypes .take() instead on one of these types.

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing the listed collection entry points, including VecDeque::remove(), LinkedList::remove(), HashMap::remove(), Vec::remove(), and the occupied-entry methods, then compare them with existing take() methods on BTreeSet, HashSet, and Option. Determine whether the proposed renames and deprecations fit Rust's API conventions and RFC process; done means reaching a documented decision on the proposal.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
api, backend-api-design
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
25/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.