# lloydmeta/frunk

Funktional generic type-level programming in Rust: HList, Coproduct, Generic, LabelledGeneric, Validated, Monoid and friends.

Repository: https://github.com/lloydmeta/frunk
Canonical: https://ross.abutalabs.com/products/frunk
Homepage: https://beachape.com/frunk/
Language: Rust
License: MIT
License Family: permissive
Topics: hlist, rust, generic, labelled-generic, generic-programming, validated, fp, coproduct, lenses, type-level, type-level-programming, datatype-generic-programming
Last push: 2026-08-01T19:32:25+00:00

## Health v2 (maintenance only)
Score: 83/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 95, release rhythm 59, longevity 100
- inputs: {"age_days": 3607, "days_push": 32, "days_rel": 60, "gap_med": 384, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1459, forks 70 (observed 2026-08-28T04:04:47.282132+00:00)

## What it is
Frunk is a Rust library providing functional programming and type-level programming tools such as HLists, Coproducts, Generic/LabelledGeneric derivations, Validated, Semigroup, Monoid, and lenses. It enables datatype-generic programming patterns in Rust with compile-time guarantees.

## Use cases
- work with heterogeneous lists in rust
- convert between structs and tuples generically
- derive generic representations for my types
- accumulate validation errors functionally
- combine monoids like tuples and options
- use coproducts instead of enums for generic code
- write type-level generic programming in rust
- access struct fields via lenses

## When to choose
- you need datatype-generic programming or generic representations in Rust
- you want statically typed heterogeneous lists or coproducts
- you need functional abstractions like Monoid, Semigroup, or Validated
- you want to build libraries that derive conversions between types

## When to avoid
- you only need simple everyday application logic without generic abstractions
- you want to avoid compile-time overhead from heavy type-level machinery
- your team is unfamiliar with functional programming concepts and type-level programming

## Facets
- artifact type: library
- maturity: stable
- function: serialization, developer-tools
- domain: programming-languages, developer-tools
- platform: rust
- tags: hlist, coproduct, type-level-programming, generic-programming, monoid, semigroup, validated, lenses, functional-programming, derives, algorithms

## Member repositories
- lloydmeta/frunk (main) score 83

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:47.282132+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T04:35:27.988468+00:00, confidence not recorded.
  - readme: https://github.com/lloydmeta/frunk (fetched 2026-08-28T04:04:47.282132+00:00, sha 386945e5b475)
  - homepage: https://beachape.com/frunk/ (fetched 2026-08-29T11:44:14.557588+00:00, sha 44136fa355b3)
  - registry_crates: https://crates.io/api/v1/crates/frunk (fetched 2026-08-29T11:44:14.566791+00:00, sha b4bd95bf0947)
- Data as of 2026-08-30T08:39:29.467469+00:00.