Haskell to Javascript compilers?

Question

I've recently came across ghcjs haskell-to-javascript compiler, but I am not sure how "ready" it is. It seems to have little activity over the last year.

Is there an equivalent to GWT in Haskell?

Also, more of a discussion question:do you think there will be a gwt haskell equivalent? Why or why not?

I just came across this when searching for ghcjs. There is a newer repo: https://github.com/ghcjs/ghcjs — Nathan, Jun 27 '12 at 12:52
See also [What is the most production-level Haskell to JavaScript compiler, to write code running in the browser?](https://stackoverflow.com/questions/6272226/what-is-the-most-production-level-haskell-to-javascript-compiler-to-write-code) — Bergi, Feb 14 '20 at 00:52

score 9 · Answer 1 · edited Jul 19 '15 at 16:45

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There are several such compilers which can be used right away.

Fay (formerly at http://fay-lang.org/, now on https://github.com/faylang/fay) The most popular and the most developed Haskell -> JS compiler. AFAIU, it implements Haskell from scratch and compiles it to JavaScript. It doesn't implement many of GHC's features, especially language extensions.
Haste (https://github.com/valderman/haste-compiler) It uses the backend of GHC to compile to javascript. As a result you can use it to compile extension containing code.

edited Jul 19 '15 at 16:45

S.L. Barth is on codidact.com

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answered Feb 16 '13 at 20:53

Konstantin Solomatov

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I have made a [very brief comparision of both](https://www.joachim-breitner.de/blog/archives/602-Running-Circle-Packing-in-the-Browser-using-Haste.html). – Joachim Breitner Jul 12 '13 at 08:47

score 7 · Answer 2 · answered Jan 09 '12 at 19:24

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Ji seems relevant, although it doesn't do any Haskell-to-JS compilation; it lets a Haskell server control a browser connected to it via AJAX.

It seems like UHC supports compiling to JavaScript and has some libraries along those lines, but I don't know what UHC's compatibility with GHC extensions is like, or how mature the support is.

I'm not convinced compiling full Haskell to JavaScript is a productive route; the overhead of implementing the likes of lazy evaluation on top of a high-level language is likely to be significant, and all the attempts so far (I haven't checked out UHC's generated code) seem to produce rather huge JavaScript (admittedly, HTTP compression mitigates this).

I don't think ghcjs is being actively developed, but it might be more stable than UHC's support. Yhc's support seems to be the furthest so far, but unfortunately Yhc is a dead project.

answered Jan 09 '12 at 19:24

ehird

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Wow, that is amazing! Ji, that is. It would be extremely wicked if there was a templating engine in there, and some kind of url routing. How in the world does it "control" the browser? I thought the only way was through AJAX! – Andriy Drozdyuk Jan 09 '12 at 20:21
@drozzy: Via AJAX, like I said :) – ehird Jan 09 '12 at 20:40
Oh, I just saw the little js file hidden in there! Haha, clever. – Andriy Drozdyuk Jan 09 '12 at 20:42
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GHCJS is actively maintained at the moment. – Joachim Breitner Jul 12 '13 at 08:47

Haskell to Javascript compilers?

2 Answers2