Coalton
Hacker ApprovedShares rank 62 of 163 programming languages by recommenders
Statically typed functional language embedded in Common Lisp, with Haskell-style types, seamless Common Lisp interop and efficient code. Caveat: getting started is hard and REPL use needs a wrapper.
Statically typed functional language embedded in Common Lisp, with Haskell-style types, seamless Common Lisp interop and efficient code. Caveat: getting started is hard and REPL use needs a wrapper.
22 people gave an opinion
- recommend it
- 20
- criticize it
- 2
- approval share
- 91%
Recommended in 10 of 13 months
- November 2025: recommended
- December 2025: recommended
- January 2026: recommended
- February 2026: recommended
- March 2026: recommended
- April 2026: recommended
- May 2026: recommended
- June 2026: not recommended
- July 2026: recommended
- August 2026: recommended
- September 2026: not recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 20 people recommend itNeeds 10 or more, met.
- 10 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 10 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Haskell-style static types inside Lisp
“if you really want Haskell types you can use Coalton, which is essentially Common Lisp with Haskell types”
Comment from 6 Oct 2026 in “Why Common Lisp is now the best programming language” “a Haskell-style language hosted inside a very dynamic one with good interop”
Comment from 22 Feb 2026 in “Parse, Don't Validate and Type-Driven Design in Rust” “Common Lisp with a Haskell-like type system”
Comment from 23 Dec 2025 in “Test, don't just verify” - Comment from 12 Mar 2026 in “SBCL: A Sanely-Bootstrappable Common Lisp (2008) [pdf]”
- Comment from 23 Aug 2026 in “A Friendly Introduction to Racket”
Seamless Common Lisp interop
“It's an FP language written in CL with seamless interop.”
Comment from 3 Nov 2025 in “Lisp: Notes on its Past and Future (1980)” “the excellent Common Lisp interop that Coalton has”
Comment from 29 May 2026 in “Coalton is an efficient, statically typed Lisp with ideas from Haskell and OCaml” “it really isn't just a language atop Lisp, but something that's integrated within it”
Comment from 6 Oct 2026 in “Why Common Lisp is now the best programming language” Enjoyable, well-made, fresh for Lisp
“Coalton is a joy to use and IMO a breath of fresh air in CL”
Comment from 16 Dec 2025 in “Liskell – Haskell Semantics with Lisp Syntax [pdf]” “I already liked Coalton, and after this change I think it's definitely going to be even better.”
Comment from 22 Mar 2026 in “A Case Against Currying” “And I mean that in a positive way as being different from CL is both an achievement”
Comment from 25 Feb 2026 in “Steel Bank Common Lisp” - Comment from 29 Apr 2026 in “Why I Still Reach for Lisp (& Scheme) Instead of Haskell”
Efficient compiled code in SBCL
“an efficient, statically typed functional programming language that supercharges Common Lisp”
Comment from 23 Aug 2026 in “A Friendly Introduction to Racket” “compiles to especially efficient code in SBCL”
Comment from 25 Feb 2026 in “Steel Bank Common Lisp”
What people warn about
Each mark is one comment
Hard to get started
“The biggest problem for me is that I can't find a simple way to get started with Coalton.”
Comment from 27 May 2026 in “Coalton is an efficient, statically typed Lisp with ideas from Haskell and OCaml” “If an LLM is needed to get set up either the language or the documentation is garbage.”
Comment from 29 May 2026 in “Coalton is an efficient, statically typed Lisp with ideas from Haskell and OCaml” Lisp syntax limits its design
“I think Coalton is cool, but I think you start to run into the limitations of Lisp syntax.”
Comment from 8 Dec 2025 in “The programmers who live in Flatland” “I'm afraid it may quickly earn similar reputation as LOOP and FORMAT.”
Comment from 2 Jan 2026 in “Extensibility: The "100% Lisp" Fallacy”
Other programming languages people recommend
The four most recommended other programming languages, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
See all 163 programming languages, rankedWhat people said
38 of the 41 comments that mention it, newest first. Each links to the original comment.
“LLMs can even write Coalton pretty well if you prefer strong, static typed all the way through”
“it really isn't just a language atop Lisp, but something that's integrated within it”
“if you really want Haskell types you can use Coalton, which is essentially Common Lisp with Haskell types”
“an efficient, statically typed functional programming language that supercharges Common Lisp”
“could also be used to build languages, supporting more modern programming paradigms”
“With Coalton and Shen they are explicitly reaching for the static-types level”
“This is entirely possible with plain lisp macros.”
“I've kept "slow" for when Coalton is used on a slower CL implementation.”
“the excellent Common Lisp interop that Coalton has”
“If an LLM is needed to get set up either the language or the documentation is garbage.”
“Coalton is a nice language project but I can't get into it because I have been using Common Lisp since 1982”
“That is a very cool web app with lots of interesting examples”
“I'm less convinced by the main value propositions (I really like my dynamic typing and CLOS)”
“The biggest problem for me is that I can't find a simple way to get started with Coalton.”
“Recently I got into stuff like Terra lang and Coalton”
“Coalton syntax is probably not unusual if you are familiar with OCaml and F#”
“Coalton makes it even better.”
“it also doesn't seem like an unfinished hobby project”
“Coalton has some evolution to go before that, but it is good and flexible enough.”
“If you know lisp, just reach for Coalton instead of Haskell”
“Just look what could be done with Coalton.”
“incredibly effective as a language for agents”
“I already liked Coalton, and after this change I think it's definitely going to be even better.”
“+1 to explore Coalton. It's also talked about on this website and often by its authors.”
“It has a type system similar to Haskell’s.”
“And I mean that in a positive way as being different from CL is both an achievement”
“Nice, pretty much what I had in mind.”
“Coalton is nice but it requires a wrapper around every form you feed a REPL or around the whole file.”
“compiles to especially efficient code in SBCL”
“a Haskell-style language hosted inside a very dynamic one with good interop”
“shifting toward something a little more structured and disciplined like Coalton”
“Not the whole language as is but proper algebraic types at least.”
“I'm afraid it may quickly earn similar reputation as LOOP and FORMAT.”
“Common Lisp with a Haskell-like type system”
“Coalton is a joy to use and IMO a breath of fresh air in CL”
“I think Coalton is cool, but I think you start to run into the limitations of Lisp syntax.”
“Lisp macros are powerful enough to implement a full ML type system in userspace as a library.”
“It's an FP language written in CL with seamless interop.”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.