Jolt: Clojure compiler implemented with Chez Scheme

# Jolt — Clojure on Scheme Source: [http://jolt-lang.net/](http://jolt-lang.net/) Jolt is a self\-hosted Clojure implementation that runs on Scheme — Chez natively, Gambit for JavaScript\. No JVM, no build step — most portable Clojure runs unchanged\. - The compiler is written in Clojure and compiles itself - Persistent data, lazy seqs, transducers, multimethods, protocols — full Clojure semantics - Real concurrency:`future`,`agent`,`pmap`, and`core\.async`on OS threads - `jolt build`emits a single standalone binary — no Scheme or JVM needed to run it The terminal on the right is jolt itself — compiled to JavaScript by the[Gambit backend](http://jolt-lang.net/docs/scheme-backends.html)— evaluating live in your browser\. It runs a[reduced build](http://jolt-lang.net/docs/scheme-backends.html#choosing_how_much_of_the_language_to_build)to keep the download small, so regex is left out here and says so if you reach for it\. jolt via Gambit → JSrepl user=\> \(\-\>\> \(range 10\) \(filter even?\) \(map \#\(\* % %\)\) \(reduce \+\)\) 120 ## Why Jolt? #### Self\-Hosted Compiler Reads Clojure, analyzes it to a host\-neutral IR, emits Scheme, and runs it — on Chez natively, or on Gambit compiled to JavaScript\. The compiler is written in Clojure and compiles itself\. #### Standalone Binaries `jolt build`ahead\-of\-time compiles a project — runtime, standard library, app, and its deps — into a single self\-contained executable\. No Chez, no JVM, no source needed to run it\. #### Real Concurrency `future`/`promise`/`agent`/`pmap`run on OS threads over a shared heap, matching JVM semantics\.`core\.async`provides channels and`go`blocks\. #### Full Numeric Tower Exact integers and bignums, exact ratios \(`\(/ 1 2\)`⇒`1/2`\), and flonum doubles\.`=`is category\-aware;`==`is value\-equality\. #### Persistent Data Immutable vectors \(32\-way tries\), cons lists, and HAMT maps/sets with Clojure value semantics\. Transients are real mutable scratch collections\. #### Clojure\-Compatible Lazy/infinite seqs, transducers, destructuring, multimethods, protocols/records, metadata, namespaces, runtime`eval`, and the full reader\. ## Quick Start Install the self\-contained`jolt`binary — it bundles the runtime, compiler, and standard library, so there's nothing else to install\. ``` # Homebrew brew install jolt-lang/jolt/jolt # or the install script (Linux / macOS) curl -sL https://raw.githubusercontent.com/jolt-lang/jolt/main/install | bash jolt -e '(+ 1 2)' # => 3 ``` Or run from a clone \(needs[Chez Scheme](https://cisco.github.io/ChezScheme/)\) — no build step, the bootstrap seed is checked in: ``` git clone --recurse-submodules https://github.com/jolt-lang/jolt.git cd jolt bin/jolt -e '(+ 1 2)' # => 3 ``` ## Usage ### Evaluate an expression ``` $ bin/jolt -e '(->> (range 10) (filter even?) (map (fn [x] (* x x))) (reduce +))' # 120 $ bin/jolt -e '(/ 1 2)' # 1/2 ``` ### Run a project ``` bin/jolt run -m myapp.core # resolve deps.edn, then run -main bin/jolt -M:test [args] # run an alias's :main-opts bin/jolt path # print the resolved source roots ``` ### Compile a standalone binary ``` bin/jolt build -m myapp.core -o myapp # single self-contained executable ./myapp arg1 arg2 # runs anywhere; args reach -main # --opt for the optimized build, --dev for an unoptimized one ``` ### nREPL ``` bin/jolt --nrepl-server # auto-resolves deps.edn, writes .nrepl-port # connect CIDER / Calva / Cursive via the .nrepl-port file, then # redefine a var and the next call sees it — no restart ``` Develop against a live process: see[REPL\-Driven Development](http://jolt-lang.net/docs/repl-driven-development.html)\. Read the[documentation](http://jolt-lang.net/docs/getting-started.html)for installation, writing libraries, and host interop\. ## Differences from Clojure Jolt targets Clojure semantics but runs on Scheme, not the JVM\. Most portable Clojure runs unchanged — persistent collections, the numeric tower, lazy seqs, transducers, multimethods, protocols/records, atoms,`future`/`agent`/`pmap`,`core\.async`, runtime`eval`, and the full reader all behave as on the JVM\. The genuine divergences: AspectDifferenceJava interopNo JVM, so no general Java interop, reflection, or`gen\-class`/`proxy`— a shimmed subset of`java\.\*`is available, plus a C[FFI](http://jolt-lang.net/docs/native-interop.html)BigDecimalNot available \(`decimal?`is always false\); the rest of the numeric tower matchesRegexCompiled by[irregex](https://github.com/ashinn/irregex), not`java\.util\.regex`— common patterns work, some Java\-specific features differ