# evincarofautumn/kitten

A statically typed concatenative systems programming language.

Repository: https://github.com/evincarofautumn/kitten
Canonical: https://ross.abutalabs.com/products/kitten
Homepage: http://kittenlang.org/
Language: Haskell
License: NOASSERTION
License Family: other
Topics: haskell, language, programming-language, concatenative, static-types, effects, forth
Last push: 2023-04-10T00:10:33+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 5370, "days_push": 1242, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1168, forks 41 (observed 2026-08-28T04:03:50.919950+00:00)

## What it is
Kitten is a statically typed, stack-based concatenative programming language with Hindley-Milner type inference and an effect/permission system for controlling side effects. This repository contains its Haskell implementation, including an interactive REPL, an interpreter, and a work-in-progress native-code compiler.

## Use cases
- learn concatenative programming
- try a statically typed stack-based language
- experiment with effect types and permissions
- write low-level code with a high-level feel
- explore type inference in a Forth-like language
- run an interactive REPL for a concatenative language

## When to choose
- you want to explore or learn concatenative/stack-based programming with static types
- you need a research language with effect tracking and deterministic resource management
- you want to contribute to or study a compiler written in Haskell

## When to avoid
- you need a stable, production-ready language with guaranteed syntax and libraries
- you require a complete native compiler toolchain today
- you need extensive documentation, ecosystem, or community support

## Facets
- artifact type: cli-tool
- maturity: experimental
- function: compiler, interpreter, programming-language, type-system, cli
- domain: programming-languages, compilers, developer-tools
- platform: windows, cli, cross-platform
- tags: concatenative, stack-based, static-typing, effect-types, haskell, forth-inspired, systems-programming, command-line, linux, macos

## Member repositories
- evincarofautumn/kitten (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:50.919950+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 2026-08-30T06:28:46.989702+00:00, confidence not recorded.
  - readme: https://github.com/evincarofautumn/kitten (fetched 2026-08-28T04:03:50.919950+00:00, sha 70a52305aaa7)
  - homepage: http://kittenlang.org/ (fetched 2026-08-29T12:34:46.766493+00:00, sha 03d1a17515d0)
  - site_page: https://kittenlang.org/documentation (fetched 2026-08-29T12:34:46.771316+00:00, sha b5b79778f0cc)
  - site_page: https://kittenlang.org/faq (fetched 2026-08-29T12:34:46.769453+00:00, sha f3d2a6786646)
- Data as of 2026-08-30T08:39:29.467469+00:00.