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.
The source code for Gerbil is hosted on Github, with the latest release available in releases.
For cutting-edge Gerbil, you can clone the repository:
$ git clone https://github.com/vyzo/gerbil.git
I have tested the bootstrap with Gambit v4.8.x, but older versions starting with v4.6.0 used to work as well.
If you want to use the latest development Gerbil from master (v0.12-DEV), then the latest version of Gambit from master is also required, as important pieces of the standard library utilize raw device support (gambit#272).
The core system has no dependencies outside Gambit, but the standard
library has several mostly optional dependencies. The only hard dependency
is libcrypto from OpenSSL; important parts of the standard library
require it.
All the other dependencies are soft.
Most library modules with foreign dependencies are not built by default,
with the exception of zlib and sqlite. These are ubiquitous, stable
and generally useful enough to warrant being present by default;
you can still disable them if you want for a minimal installation.
In ubuntu, you can install the dependencies for a default installation with:
$ sudo apt-get install openssl libssl-dev sqlite3 libsqlite3-dev
The optional libraries can be enabled or disabled at build-time
by editing $GERBIL_HOME/src/std/build-features.ss.
You can also enable features later, by editing build-features.ss and
running build_stdlib.sh in $GERBIL_HOME/src/.
After unpacking a release or checking out the source code from Github, let
$GERBIL_HOME be the top directory of Gerbil.
Then:
$ cd $GERBIL_HOME/src
$ ./build.sh
If you are building in MacOSX and want to use the homebrew OpenSSL,
then you need to specify appropriate CPPFLAGS and LDFLAGS.
For instance:
$ LDFLAGS=-L/usr/local/opt/openssl/lib \
CPPFLAGS=-I/usr/local/opt/openssl/include \
./build.sh
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.
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 Gerbil wiki at Github contains a small but growing collection of pages that can help you get started with Gerbil programming.
- The Gerbil Tutorial provides a few hands-on guides on Gerbil programming.
- The Gerbil Core Prelude documents the core language prelude.
- The Gerbil Standard Library Overview provides an overview of the Gerbil stdlib.
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.
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 polluted everything with more than a (C) vyzo at hackzen.org, would read like this:
(C) 2007-2017 Dimitris Vyzovitis <vyzo -at- hackzen.org>
Gerbil is Free Software, distributed under the GNU LGPLv2.1 or later
and the Apache 2.0 license.
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 work with the Gerbil macro system, 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 I am 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.