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Small Clojure Interpreter

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A tiny implementation of Clojure in Clojure.


You want to evaluate code from user input, but eval isn't safe or simply doesn't work.

This library works with:

  • Clojure on the JVM
  • Clojure compiled with GraalVM native
  • ClojureScript, even when compiled with :advanced

It is used as the interpreter for babashka.


Experimental. Breaking changes are expected to happen at this phase.


Use as a dependency:

[borkdude/sci "0.0.1"]


(require '[sci.core :as sci])
(sci/eval-string "(inc 1)") => ;; 2
(sci/eval-string "(inc x)" {:bindings {'x 2}} ;;=> 3

Anonymous functions literals are allowed with currently up to three positional arguments. This is an arbitrary limit and may be changed in the future.

(sci/eval-string "(#(+ %1 %2 %3) 1 2 3)") => ;; 6

Currently, only the special forms/macros quote, if, when, and, or, -> and ->> are supported.

By default sci only enables access to the pure non-side-effecting functions in Clojure. More functions can be enabled, at your own risk, using :bindings:

user=> (sci/eval-string "(println \"hello\")" {:bindings {'println println}})

More examples of what is currently possible can be found at babashka.


Run all tests:


This will run tests on the JVM, Node.js and using a GraalVM binary.

Test the native version:

SCI_TEST_ENV=native script/test


You will need leiningen and GraalVM.



Copyright © 2019 Michiel Borkent

Distributed under the EPL License, same as Clojure. See LICENSE.

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