PSpsibi·Nov 26, 2013
It's features, examples and other information can be found here: https://github.com/faylang/fay/wiki
In FAY: Subset of Haskell that compiles to JavaScriptfaylang
fay
Haskell2013–2021
faylang / fay
fay
A proper subset of Haskell that compiles to JavaScript
12Distinct people
13Mentions
0Explicit recommenders
1.3KGitHub stars
What to know before exploring
What it is
A proper subset of Haskell that compiles to JavaScript
GitHub
Where it is used
No documented product use was verified in the last source check.
What people are saying
No recommendation phrase was found in the indexed comments.
No classified warning is attached to this page. Read the discussions before treating silence as approval.
Also in these discussions
- ghcjs/ghcjs · linked in 2 of the same discussions
- ku-fpg/sunroof-compiler · linked in 2 of the same discussions
Mentioned in the same Hacker News threads. That is not proof they are substitutes.
This week on Hacker News
Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 9:02:44 AM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year13 dated mentions
Observed mentions: 2013-05-29 17:47:24 UTC to 2021-02-27 01:12:02 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2013 | 2013-01-01 00:00:00 UTC | 2014-01-01 00:00:00 UTC | 8 | 1 | 7 |
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 3 | 0 | 3 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 1 | 1 | 0 |
What Hacker News says
8 sourcesFAY: Subset of Haskell that compiles to JavaScript
2 points · Open discussion"Frege is thought as a substitute for this missing GHC port. While not derived from any existing Haskell implementation, it is more or less equivalent to Haskell 2010. Please see the wiki page that details the differences."
So now Haskell can produce native executable code, run in a JVM and as subset of it (https://github.com/faylang/fay/wiki) run in the browser. Now there is no excuse for me to NOT using Haskell ;)
Thanks for bringing Haskell to the JVM!
In Frege: A JVM pure functional programming language in the spirit of HaskellThis explains more. https://github.com/paf31/purescript
It looks nice and simple to use.
I guess it is similar to these:
https://github.com/faylang/fay/wiki
https://github.com/evancz/Elm
https://github.com/puffnfresh/roy
This one isn't mentioned much but has a similar goal in that the idea is to bring strong typing and a nicer functional style to web programming:
https://github.com/ku-fpg/sunroof-compiler
A lot of info on similar here:
http://www.haskell.org/haskellwiki/The_JavaScript_Problem
In Try PureScriptIf your needs fall towards JS as the target vs. the source language, then it's worth having a look at Fay[1] and GHCJS[2]. Both allow calls from regular Javascript, but Fay currently has a much better interface for that vs. GHCJS' still very low-level support.
[1] https://github.com/faylang/fay/wiki
[2] https://github.com/ghcjs/ghcjs
In Why monads have not taken the Common Lisp world by storm (2008)If you are looking for Haskell, you can take a look at Fay (https://github.com/faylang/fay/wiki).
In Kal – a clean JavaScript alternative without callbacksThere's also Fay <https://github.com/faylang/fay/wiki> which provides a lighter-weight compilation of Haskell to JS, omitting stuff like threading and type classes.
Nice thing about Fay is you can read the generated javascript and see the 1:1 correspondance to the haskell code. This can be a nice way to get an intuition abvout how thunks are used to implement eg, infinite length lazy lists in haskell. There is also a live IDE <http://ide.fay-lang.org/>. I think this makes Fay an excellent teaching tool.
The way it seems to be shaping up is that ghcjs will be used for big serious projects where a javascript runtime that is measured in (IIRC) megabytes is acceptable and the full power of haskell is needed. While fay will be used as glue code for projects that are mostly written in server side Haskell and want to run some code in the browser
Read the rest
, with access to the same types used on sever-side to eg, make AJAX nicer. Fay's entire runtime is 16 kb (unminified; with minification and other size optimisations a complete program can be as small as 3 kb) <https://github.com/faylang/fay/blob/master/js/runtime.js> which makes it work well in these niches.
For those interested in compiling down to Javascript with a strongly and statically typed language, there's a brilliant proper subset of Haskell that compiles down to Javascript called "Fay": https://github.com/faylang/fay/wiki
In Elm at Prezi