Gerbil Scheme

Gerbil is an opinionated dialect of Scheme designed for Systems Programming, with a state of the art macro and module system on top of the Gambit runtime.

The macro system is based on quote-syntax, and provides the full meta-syntactic tower with a native implementation of syntax-case. It also provides a full-blown module system, similar to PLT Scheme's (sorry, Racket) modules. The main difference from Racket is that Gerbil modules are single instantiation, supporting high performance ahead of time compilation and compiled macros.

• Installation
• Using Gerbil
• Documentation
• License and Copyright
• Epilogue

Installation

The source code for Gerbil is hosted on Github, with the latest release available in releases.

For installation instructions see the Guide, rendered online here.

Using Gerbil

The Gerbil interpreter is $GERBIL_HOME/bin/gxi, and the compiler is $GERBIL_HOME/bin/gxc.

If you want an interactive Gerbil shell just execute the interpreter directly by running gxi.

For "hello, world" see the Guide.

Documentation

The documentation is a work in progress, but there are some resources that should get you started:

• The Introduction to Gerbil is an introductory guide for seasoned Schemers.
• The Getting Started page covers the very basics of setting up your Gerbil installation and writing your first code.
• The Gerbil Tutorial provides a few hands-on guides on Gerbil programming.
• The Gerbil Reference is the reference documentation for the Gerbil runtime and standard library.

The documentation is automatically rendered online at cons.io. You can render it locally by running doc/build.sh, which will leave the html output in doc/.vuepress/dist; the script uses vuepress and requires npm to be installed.

Probably the best way to dive into Gerbil is by reading the sources, as all the main language features are exercised in one way or another within the implementation.

Depending on your inclinations, there are several starting points:

• If you are interested in general purpose programming, then you should look at the stdlib sources.
• If you are interested in Gerbil macrology, then the place to start is the core prelude. This is the language that you get in the interpreter and what is available when writing a new module without explicitly specifying a prelude.
• If you are interested in the Gerbil expander internals, then you should look at the expander sources.
• If you are interested in the Gerbil compiler internals, then you should look at the compiler sources.

For questions and support, you can come say hi in #gerbil-scheme on irc at freenode.net. You can also find us on gitter in #gerbil-scheme.

License and Copyright

Source Code

The source code is distributed with the Gambit license; that means that Gerbil on Gambit is dual licensed under LGPLv2.1 and Apache 2.0.

Gerbil's primary author and maintainer is vyzo-at-hackzen.org, aka in the Net as Dimitris Vyzovitis. The obligatory copyright notice, had I bothered and polluted everything with more than a (C) vyzo, would read like this:

© 2007-2019 Dimitris Vyzovitis and contributors
Gerbil is Free Software, distributed under the GNU LGPLv2.1 or later
and the Apache 2.0 license.

The implementations of srfi 115 and srfi 159 come from Chibi, as these are the only available reference implementations. As such, they are © Alex Shinn and distributed under a BSD-style license.

Logo

The Gerbil Scheme logo is © 2019 Brad Christensen. The logo, its variations, and derivatives found within the official Gerbil Scheme code repository are provided under a royalty-free non-exclusive license for use by any person or entity wanting to use them solely in the context of the Gerbil Scheme programming language, including for commercial use, and grants them the rights to copy, distribute, display, and create derivative works so long as those derivatives are made available under this same license.

Creators of derivatives are encouraged to offer them for inclusion to the official code or associated Gerbil Scheme repository, where upon acceptance they will be easier to find and use (for example in documentation and acticles) by the community at large. Furthermore, a derivative's terms of use will be made available by the statements here.

This license in no way guarantees the availability of the logo, or any of its variations or derivitives in the future.

Epilogue

Gerbil has been my private Scheme for many years, evolved out of a set of common macros that i used across different implementations and eventually a full-blown PLT macro language. As such I have had multiple backends that supported the Gerbil dialect, but I have elected to base the canonical version of Gerbil on Gambit.

At the prompting of some friends (they know who they are), who had seen private versions of Gerbil, I decided to release it in public with a clean bootstrap version that bootstraps on gambit with a precompiled version of the macro system and compiler. That means that the system is entirely self-hosted in Gambit.

Gerbil is under continuous use and development. The core language has been stable for a while, but we are busy porting batteries, adding features, fixing bugs, and expanding the scope of syntactic abstraction.

Patches (even for typos in the comments) are always welcome. No copyright assignment ever, you keep what you contribute.