I'm yet to dive into Jisp, but from a few seconds of looking at the page I think the difference is quite obvious. ClojureScript implements semantics which are very different from JS on top of it, it comes with it's own runtime library, it relies on Google Closure Compiler to optimize it's JS which would be rather large otherwise. I don't know of any page where you get side by side clojurescript -> generated js code comparison. It's similar to js-of-ocaml and many other LanguageX-in-JS projects.
Jisp on the other hand looks like it's a straightforward transpiler, with more or less one to one mapping between Jisp and JS constructs, without the need for providing large runtime. It looks like CoffeeScript with a sexps-based syntax. It reminds me of Hy language and Lisp Flavored Erlang, which I feel are similar projects (for Python and Erlang respectively).
There are at least 3 other Lisp dialects with similar philosophy on JS (excluding ClojureScript) out there, but when I last looked on them I wasn't convinced by any one and I stayed with LiveScript for work and I started exploring ClojureScript. I'll definitely take a look at Jisp now as a potential LS replacement.
Too late to edit: I just found ki (http://ki-lang.org/) which is a Lisp implemented as a set of macros on top of Sweet.js, which means you can a) freely mix it with JS; b) compose it easily with other Sweet.js macros. Now this is huge: all those compile-to-JS languages are nice, but they don't compose at all, ie. if you write Coffee and decide that there's a neat Sweet.js macro you'd like to use you're out of luck. You can't import just one operator (for example `|>`) from LiveScript to Coffee, you need to change the whole language. While this is not a big problem for me personally, it's still an unnecessary overhead.
Sweet.js, which is modeled after Racket parse transforms, allows for importing only those syntactic extensions you're interested in and most of those macros will probably compose nicely. I always supported the idea of Sweet.js, but I didn't use it because its library of available macros was too small (I'd need to reimplement too much of LiveScript) and macros in syntaxes as complicated as JS are a huge pain to properly display in editors. ki would probably solve the latter problem for me - with syntax that regular adding support for it to js-mode in Emacs shouldn't be too hard. This could mean that it's time to try Sweet.js for real!
Hi! There are a few of us here, I saw at least 4 or 5 users mention LS on JS/Coffee/other related threads. I'm saying this because some month ago I was worried about LS future: there is nothing happening on the mailing list and commits on github are rather infrequent. But when I found a bug in LS compiler and fixed it the PR was processed in a reasonable time and the people were there to help. So I guess LS is just mature and somewhat complete at this point and not stagnating :) Which is very nice, because LS is the only lang I know of which gathers so many very useful features in a single language. This is even more true now when generators support was added. The only problem with LS is lack of source maps, but as it compiles to a rather readable JS it's not that bad. It probably limits its popularity greatly, though :(
its distinguishing feature is that it starts with idiomatic javascript and carefully adds lisp features to that, rather than porting an existing lisp to javascript. the readme calls it a "javascript-first approach" and notes that it was heavily inspired by coffeescript.
Came in here to post the same thing. As another Lisp to JavaScript transpiler and the popularity and support for ClojureScript already I think there needs to be some pretty compelling differences.
It needs to be different than ClojureScript as well as more than a dozen other lisp-to-js projects. [1]
These are fun projects, and I don't doubt that the authors and a few individuals have or will get great use of of it, but the market is saturated with languages that compile JS right now and very few stick out or are likely to get critical mass. Even Coffeescript, which is probably the most popular one, has a small community.
I personally am all about encouraging people to make all the new languages and tools they want, even if it duplicates existing stuff. But I also agree that the comparison with the similar stuff should probably be mentioned.
There's lots of reasons for a hobby or research project to reinvent a particular wheel. Not everything has to be efficient or practical. But it's probably at least worth considering.
I imagine the pain of setting clojurescript or cljx up with repls and such will soon be eclipsed by one of these dead simple compile to js lisps which seem to be coming out with increasing speed.
Just musing, but just supporting a js target could replace clojure in entirety since the jvm also has a js runtime.
