Associative container mapping keys to multiple values, supporting insert/insert_many, flat iteration, customizable hasher and FromIterator conversion — a thin HashMap-backed multimap implementation.
This is a Kotlin Multiplatform line-by-line transliteration port of havarnov/multimap.
Original Project: This port is based on havarnov/multimap. All design credit and project intent belong to the upstream authors; this repository is a faithful port to Kotlin Multiplatform with no behavioural changes intended.
This is an in-progress port. The goal is feature parity with the upstream Rust crate while providing a native Kotlin Multiplatform API. Every Kotlin file carries a // port-lint: source <path> header naming its upstream Rust counterpart so the AST-distance tool can track provenance.
havarnov/multimapThe text below is reproduced and lightly edited from
https://github.com/havarnov/multimap. It is the upstream project's own description and remains under the upstream authors' authorship; links have been rewritten to absolute upstream URLs so they continue to resolve from this repository.
This is a multimap implementation for Rust. Implemented as a thin wrapper around
std::collections::HashMap.
FromIterator<(K, Vec<V>)> #48.flat_iter and flat_iter_mutget and get_mut could panic.multimap! macro fixes; allow trailing comma, naming hygiene and create with
enough capacity for all elements.#![forbid(unsafe_code)].Cargo.toml.MultiMap::insert_many.MultiMap::insert_many_from_slice.HashMap.mut.Licensed under either of
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
dependencies {
implementation("io.github.kotlinmania:multimap-kotlin:0.1.2")
}
./gradlew build
./gradlew test
See AGENTS.md and CLAUDE.md for translator discipline, port-lint header convention, and Rust → Kotlin idiom mapping.
This Kotlin port is distributed under the same MIT license as the upstream havarnov/multimap. See LICENSE (and any sibling LICENSE-* / NOTICE files mirrored from upstream) for the full text.
Original work copyrighted by the multimap authors.
Kotlin port: Copyright (c) 2026 Sydney Renee and The Solace Project.
Thanks to the havarnov/multimap maintainers and contributors for the original Rust implementation. This port reproduces their work in Kotlin Multiplatform; bug reports about upstream design or behavior should go to the upstream repository.
extern crate multimap;
use multimap::MultiMap;
fn main () {
let mut map = MultiMap::new();
map.insert("key1", 42);
map.insert("key1", 1337);
map.insert("key2", 2332);
assert_eq!(map["key1"], 42);
assert_eq!(map.get("key1"), Some(&42));
assert_eq!(map.get_vec("key1"), Some(&vec![42, 1337]));
}
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