hazelgrove/hazel
Hazel, a live functional programming environment with typed holes observed · 2026-09-03
Health v2 · maintenance only
68/100
- Activity 100
- Release rhythm 8
- Longevity 100
How is this computed?
round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10) — computed 2026-09-03. Adoption (stars, forks) is never an input.
- gap_med: n/a
- age_days: 3506
- days_rel: 422
- days_push: 0
- n_releases_24m: 1
Adoption not part of the score
1142 stars · 67 forks observed · 2026-09-03
What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded
Hazel is a web-based live functional programming environment for an Elm/ML-like language built around typed holes, allowing typechecking, editing, and even running incomplete programs. It is a research project implemented in Reason/OCaml and compiled to the browser, with no meaningless editor states.
Use cases
- experiment with typed-hole-driven development in a functional language
- try a live programming environment that runs incomplete programs
- explore research on semantic foundations for program editors
- teach type theory and functional programming interactively
- edit functional programs without ever hitting invalid editor states
When to choose
- you want to experiment with or contribute to research on typed holes and live programming
- you need an environment that gives feedback on incomplete or erroneous programs
- you are teaching or learning functional programming with immediate type feedback
When to avoid
- you need a production-ready IDE for mainstream languages
- you want a stable tool with long-term ecosystem support
- you need offline desktop tooling or integration with existing compilers
Facets
application · maturity active
editor interpreter type-system programming-language programming-languages developer-tools text-editors education browser cross-platform typed-holes functional-programming live-programming reasonml ocaml research-project web-based-ide web-server
2 sources
- readme: https://github.com/hazelgrove/hazel · fetched 2026-09-03 · d43c38fe5250
- homepage: http://hazel.org/ · fetched 2026-08-29 · c166b9f33347
Member repositories
| Repository | Role | Health v2 |
|---|---|---|
| hazelgrove/hazel | main | 68 |
For agents
markdown · JSON · MCP: product_card(name="hazelgrove/hazel")
Data as of 2026-08-30T08:39:29.467469+00:00 · Report a problem