Jolt: Clojure compiler implemented with Chez Scheme

Clojure fans cheer a tiny no-fuss app maker, while skeptics ask: why not just use the usual tools

TLDR: Jolt is a new way to run Clojure apps as small standalone programs, even in a browser demo, without the usual heavyweight setup. Fans love the lighter approach, but skeptics immediately asked the big question: is it truly useful, or just another option for already spoiled programmers?

A new project called Jolt just strutted into the coding scene promising something catnip-level exciting to a certain kind of programmer: a way to build and run Clojure apps without dragging in the giant Java setup people usually associate with it. In plain English, it means smaller, simpler apps that can even be packed into a single standalone file. One early commenter, mark_l_watson, was already sold, gushing that it "works great" for making small self-contained apps on macOS and Linux. That set the tone fast: this was less "hmm, interesting" and more "finally, another way to do this!"

But of course, no internet launch is complete without at least one record-scratch moment. While fans celebrated a slimmer, more portable option, another commenter immediately poked at the browser angle: if Jolt can run there too, what does it actually offer over plain ClojureScript, the older browser-friendly version many already know? That was the big tension in the thread: is this a breakthrough, or just another flavor for language nerds to argue about? Even the jokes got in on the chaos, with one drive-by commenter swerving into an unrelated pun by posting Jolt Physics, as if the thread needed a crossover episode. Meanwhile, the author popped in with a calm "glad to answer any questions," which only made the rest of the thread feel more like a lively fan debate happening around the creator at the center of it all.

Key Points

  • Jolt is a self-hosted Clojure implementation that runs on Scheme, using Chez Scheme natively and Gambit for JavaScript.
  • The compiler is written in Clojure and can compile itself.
  • Jolt claims support for full Clojure semantics, including persistent data, lazy seqs, transducers, multimethods, and protocols.
  • It provides concurrency features including future, agent, pmap, and core.async on OS threads.
  • `jolt build` can emit a single standalone binary, and the browser demo runs Jolt compiled to JavaScript with a reduced feature set that omits regex.

Hottest takes

"works great to build small self contained apps" — mark_l_watson
"good to have even more (and more slim!) ways to run Clojure" — tosh
"what does Jolt on Gambit offer over plain ClojureScript?" — kccqzy
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