cdcf569506
- PEG-based Clojure reader (symbols, keywords, numbers, strings, lists, vectors, maps, sets, quote forms, reader macros, metadata) - Tree-walking evaluator (quote, do, if, def, fn*, let*, loop*/recur, syntax-quote/unquote/unquote-splicing, macro system, ns/require/in-ns) - 95+ clojure.core functions (predicates, math, collections, seq ops, higher-order, atoms, I/O) - Public API (init, eval-string, eval-string*) - REPL (jolt/main.janet) - 7 test suites, all green - MIT license
67 lines
2.3 KiB
Markdown
67 lines
2.3 KiB
Markdown
# Jolt
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A Clojure interpreter running on [Janet](https://janet-lang.org). Jolt reads Clojure source text, evaluates it using an interpreter written in pure Janet, and exposes a Clojure-compatible standard library.
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## What's inside
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Jolt implements the core of Clojure in a single-process, no-dependency Janet project:
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**Reader** — A recursive descent parser for Clojure syntax: symbols, keywords, numbers, strings, characters, lists, vectors, maps, sets, quote forms, reader macros (`#()`, `#_`, `#?`), metadata, deref, and tagged literals.
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**Evaluator** — A tree-walking interpreter with special forms (`quote`, `do`, `if`, `def`, `fn*`, `let*`, `loop*`/`recur`), syntax-quote with unquote and unquote-splicing, a macro system, and namespace forms (`ns`, `require`, `in-ns`).
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**Core library** — 95+ functions from `clojure.core`: predicates, math with Clojure arity semantics, comparison, collection operations (conj, assoc, dissoc, get, merge, keys, vals), sequence operations (map, filter, reduce, take, drop, take-while, drop-while, concat, reverse, sort, distinct, group-by, partition), range and repeat, higher-order functions (comp, complement, constantly, juxt, memoize, partial), collection constructors, string functions, I/O, and atoms.
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## Build
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```
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jpm build
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```
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This compiles `src/jolt/*.janet` into a standalone `build/jolt` executable. Requires Janet ≥ 1.36 and `jpm`.
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## Run
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```
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build/jolt
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```
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Drops into a read-eval-print loop where you can type Clojure expressions:
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```
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user=> (+ 1 2)
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3
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user=> (map inc [1 2 3])
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[2 3 4]
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user=> (defn fib [n] (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2)))))
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#'user/fib
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user=> (fib 10)
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55
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```
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## Use as a library
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```janet
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(use jolt/api)
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(def ctx (init))
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(eval-string ctx "(+ 1 2)") ;; → 3
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(eval-string ctx "(map inc [1 2 3])") ;; → [2 3 4]
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(eval-string ctx "(def x 42)") ;; → #'user/x
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(eval-string ctx "x") ;; → 42
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```
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`(init)` returns a context with `clojure.core` loaded. Pass it to `eval-string` to evaluate Clojure source. Each context is isolated — use separate contexts for separate evaluation environments.
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To pre-populate a context with values:
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```janet
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(use jolt/api)
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(def ctx (init {:namespaces {"user" {"greeting" "hello"}}}))
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(eval-string ctx "(str greeting \" world\")") ;; → "hello world"
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```
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## License
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[Eclipse Public License 1.0](https://opensource.org/licenses/EPL-1.0)
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