Tracking Issue for BTreeMap::merge

[asder8215]

Feature gate: #![feature(btree_merge)]

This is a tracking issue for rust-lang/libs-team#739

It adds a method similar to BTreeMap::append with merging two BTreeMaps in O(n + m) complexity, but allows the user to specify a callback function to handle what the resulting value should be for conflicting keys.

Public API

// use std::collections::BTreeMap; or use alloc::collections::btree_map; 

impl <K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
    pub fn merge(&mut self, other: BTreeMap<K, V, A>, conflict: impl FnMut(&K, V, V) -> V) { ... }
}

Steps / History

(Remember to update the S-tracking-* label when checking boxes.)

• ACP: ACP: Add BTreeMap::append_with libs-team#739
• Implementation:
  • implement BTreeMap::merge #151981
  • BTreeMap::merge optimized #152418
• Optimization Issue: Optimizations to be performed on BTreeMap::merge #153040
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• None yet.

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

[asder8215]

@rustbot label -S-tracking-unimplemented