A new r7rs Scheme implementation, designed to run within a Common Lisp environment.
Airship Scheme now is on IRC! This project uses
irc.libera.chat as its IRC network. The main
channel is #airship, but #scheme and #lisp also might be useful.
The name was inspired by the "Imperial Airship Scheme" Wikipedia
article, via
a comment someone else made on Hacker
News in early 2017.
Prior to that, this project used the working title cl-scheme. The
old name is more descriptive, but considerably less interesting. The
#scheme channel on Freenode IRC loved the name, which was shortened
to "Airship Scheme" for simplicity.
The primary repository is located here. Progress towards completion is measured under the milestones here.
Airship Scheme is a new implementation of the Scheme programming language, implemented in Common Lisp and designed to run within a Common Lisp environment. The embedded nature of this architecture allows programs to run both Scheme and Common Lisp code in the same runtime.
There are many existing implementations that compile Scheme to languages like C or JavaScript. With the choice of Common Lisp, the host language already contains many elements that Scheme requires. The host CL's data structures include the cons cell (or cons pair) data structure and the numeric tower, both of which can be used in the Scheme itself.
On the other hand, the Scheme to CL compilation process is no longer as trivial as it was in the days of Pseudoscheme because Common Lisp and Scheme have drifted further apart as languages over the past few decades, making some of the assumptions of past approaches no longer viable. There are also syntactic incompatibilities, meaning that a fully conforming Scheme cannot simply use the host CL's reader.
This project depends on sharing a large amount of code initially
written for a Common Lisp first person 3D game engine called Zombie
Raptor. Parts of that effort were spun off into the zr-utils utility
library, which is a work in progress library with an unstable API. In
fact, that library was spun off precisely to be used as a shared
dependency between the game engine and this project. All of these are
still incomplete.
As of 2024, most of the recent work towards this project has been written as general purpose programming language internals instead of happening directly in this repository. In particular, there's also a vector and shader language, ZRVL, which is of more direct importance to the game engine. The smaller scope of this other language means that it is a more suitable place to develop the shared internals of programming languages that target Common Lisp implementations as a CPU runtime. Additionally, ZRVL will also target SPIR-V to be used for graphics shaders, but the semantics of Scheme would make it challenging to do so without subsetting the language.
Work on this project will resume when the internals of ZRVL are spun off as a useful intermediate representation that Airship Scheme can also benefit from.
This project is primarily aimed at both Common Lispers and Schemers.
It offers Scheme as a convenient library: it's no harder to install or
use than any other CL library. Most Scheme libraries will be usable in
Common Lisp, and a lot of core-or-SRFI Scheme functionality will be
provided in a CL-compatible form. Custom sequences not found in CL
will be implemented via trivial-extensible-sequences. Eventually, a
reader macro could be provided that provides most of the benefits of
Scheme's additional syntax while still using the CL reader.
It offers the potential of getting a high-performance implementation for "free" by taking advantage of high-performance CL compilers like SBCL. Schemers will be able to wrap libraries written in CL, which will more than double the number of libraries available. These wrapped CL libraries will feel a lot "Lispier" than wrapped C libraries because CL is a closely related programming language. Additionally, almost all of the Common Lisp standard library will be wrapped.
See INSTALL.md for complete installation instructions.
The fastest way to get a Common Lisp development environment for someone who doesn't currently have one is to install Portacle.
Then, inside of the Quicklisp local-projects directory:
git clone https://gitlab.com/zombie-raptor/zr-utils.git
git clone https://gitlab.com/mbabich/airship-scheme.gitThen you can run this at the Common Lisp REPL:
(ql:quickload :airship-scheme)See CONTRIBUTING.md for contributing, terminology, and style guidelines.
MIT License. See LICENSE.txt for the license text.
This section is currently incomplete because the programming language is not functional at the moment.