Skip to content


Subversion checkout URL

You can clone with
Download ZIP
A Lisp-like language implemented in C++
C++ C
branch: master


Ciel is a lisp-like language implemented in C++.  What Clojure is to
Java, Ciel is designed to be to C++.  The idea was to see how far one could
get using off-the-shelf C++ code to build a usable system.

To build Ciel you will need:

* The Boehm GC (
* CLN, the Class Library for Numbers (
* g++

To build Ciel, just install libgc and libcln, then make.  Ciel has been
built and run on Linux and OS X Snow Leopard.

At the moment Ciel is interpreted, but it is designed to be compiled
straighforwardly into C++, and thence into native code.  Some examples of
hand-compiled functions that can be dynamically loaded into the REPL and
run are included.


Lambda is spelled FN.

SETQ/SETF/SET! is spelled SET.  There is no separate definition form.

Ciel supports Scheme-style dotted argument lists, but parameters are
passed as vectors, not lists.  Vectors are denoted with square brackets,
and can be extended with the VPE (vector-push-extend) operator.

You can assign special operators.  So, for example, this works:

(set lambda fn)
(set def set)
(def vector (lambda x x))
(vector 1 2 3)

This is all not even half-baked at the moment.  I'm mostly putting this
out there to see if there is any interest in it at all.  If there is I'd
be happy to clean things up and add capabilities.
Something went wrong with that request. Please try again.