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Cozy is a tool that synthesizes data structure implementations from simple high-level specifications. It automatically chooses a good representation of your data and efficient method implementations.

Cozy can greatly simplify the task of writing software modules with private state. In most cases, Cozy specifications are short and self-documenting, and are therefore much easier to maintain than handwritten implementations. Occasionally Cozy can discover deep optimizations that human developers shy away from.

Currently, Cozy can generate code for C++ and Java.



  • Python >= 3.5
  • The Python modules listed in requirements.txt; install them with pip3 install -r requirements.txt.

If you run into trouble, consult the wiki page on troubleshooting setup and installation.

To list all command-line options (and ensure that everything is correctly installed):

$ git clone
$ cd cozy
$ pip3 install -r requirements.txt
$ python3 -m cozy --help

To synthesize an implementation ( of the specification examples/basic.ds:

$ python3 -m cozy examples/basic.ds --java

The cozy executable

If you want to install the global executable cozy on your system:

$ pip3 install .

Installation is optional; Cozy can run in this source directory as described in the "Quickstart" section. Running cozy [ARGS] behaves just like python3 -m cozy [ARGS] would.

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