An experimental new programming language
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pl-checklist.txt various cosmetic fixes to build stuff Feb 4, 2017

Build Status


Gypsum is an experimental new programming language. In the future, it will be useful for developing high-performance desktop and web applications and games.

Gypsum is a compiled, statically-typed, object-oriented language. Once the compiler is more fully implemented, it will be functional as well. The compiler generates bytecode for a virtual machine, CodeSwitch. CodeSwitch currently provides basic interpretation and memory management. Eventually, it will have an optimizing JIT compiler and will be able to execute bytecode for other languages.

The syntax of Gypsum is inspired by Python and Scala. It is designed to be simple, requiring less extraneous punctuation than most languages. Here's how "hello world" is written:

def main =
  print("Hello, world!\n")

You can find several simple programs in the examples directory. You can find instructions for running them in examples/


Gypsum compiler

The Gypsum compiler can be found in the gypsum directory. It is written in Python (2.7). Once the language is mostly complete, the compiler will be rewritten in Gypsum.

You can build an installable Python package with Bazel and install it with pip.

bazel build :gypsum
sudo pip install --upgrade bazel-bin/gypsum-0.tar.gz

gypsumc -o program.csp

To test the compiler:

bazel test gypsum:all

CodeSwitch virtual machine

The CodeSwitch virtual machine can be found in the codeswitch directory. It is intended to be minimal. Currently, it can load packages (.csp files), manage memory (including a basic copying garbage collector), and interpret bytecode (with a simple switch loop).

To build and test the VM:

bazel test codeswitch:all

To build a standalone command line tool which can run Gypsum code:

bazel build codeswitch:codeswitch_cmd

See the examples directory for some programs to try out.

Standard library

The standard library can be found in the std directory. It includes some basic data structures (Option, Tuple, Dict, Set, ...) and some useful traits (Eq, Hash, Iter, ...). All gypsum packages depend on the standard library by default. There is also a std/io library that provides access to files.

To build the standard library:

bazel build std std/io

Other goodies

An experimental Emacs major mode for Gypsum is in tools/gypsum-mode.el. It provides basic syntax highlighting.

To install, use M-x package-install-file, then add this to your .emacs:

(require 'gypsum-mode)


Gypsum and CodeSwitch are developed and tested on Ubuntu 14.04. They have also been tested in MacOS Sierra and Ubuntu 16.04. They may work on other platforms with some light modification.

CodeSwitch currently only supports 64-bit x86 platforms. Support for other architectures will be added in the future.


  • Bazel is needed to build and test everything. It's also needed to run the examples.
  • You will need Java 1.8 to run Bazel. It includes installation instructions on how to set that up if you don't have it installed already.
  • Python 2.7 is needed to run the compiler and to generate some files needed for CodeSwitch.
  • PyYAML is needed to parse some data files needed for the Gypsum compiler and for CodeSwitch. Bazel will fetch it automatically when you build Gypsum.
  • Doxygen is needed to generate documentation.

Gypsum and CodeSwitch were developed and tested on Ubuntu 16.04 and MacOS X 10.11. They may work on other platforms with some modification, but nothing else is officially supported right now.