My programs and libraries written in Hare

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3 days ago

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3 days ago

#The Hare programming language

Hare is a systems programming language and a work-in-progress.


  1. Trust the programmer.
  2. Provide tools the programmer may use when they don't trust themselves.
  3. Prefer explicit behavior over implicit behavior.
  4. A good program must be both correct and simple.

#Early development secrecy

Hello, onlooker! Please keep this project a secret. Feel free to mess around with it and send feedback (we're in #hare on irc.libera.chat), but please keep it to yourself. We don't want to announce this project until it's much, much more mature.

Email Drew DeVault to request access to the private bug tracker, mailing lists, and IRC channel.

#Build status

Linux (x86_64)
Build status for Linux
FreeBSD (x86_64)
Build status for FreeBSD


For information about bootstrapping a working Hare toolchain from scratch, see Hare Installation on the website.


This is a work in progress! The process for bootstrapping Hare is as follows:

  1. Write the bootstrap compiler in C, and a specification which describes the language.
  2. Write the build driver in Hare, and at least as much of the standard library which is necessary to make it work.
  3. Write the hosted compiler in Hare. At this point, Hare is fully bootstrapped.
  4. Expand the standard library until it's useful for general purpose systems programming. Write programs in Hare. Provide benefit to society.

Right now, stages 1 and 2 are mostly complete, and we're working on stages 3 and 4 in parallel.

Explanation of terms:

  • bootstrap compiler: a Hare compiler written in C, primarily used for the purpose of bringing up a working Hare toolchain from scratch.
  • hosted compiler: a more sophisticated Hare compiler, written in Hare, designed to be the compiler used for day-to-day language use.
  • build driver: similar to make, its purpose is to collect source files, track their dependencies, and build them into Hare programs.


All contributors are required to "sign-off" their commits (using git commit -s) to indicate that they have agreed to the Developer Certificate of Origin:

Developer Certificate of Origin
Version 1.1

Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
1 Letterman Drive
Suite D4700
San Francisco, CA, 94129

Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.

Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.

Please send patches to the hare-dev mailing list to send your changes upstream.


We are not your lawyer, but here is a simple explanation of the intention behind the Hare licenses.

The Hare standard library is available under the terms of the Mozilla Public License (MPL). You can freely link to the standard library with software distributed under any license, but if you modify the standard library, you must release your derivative works under the MPL as well.

The executables - the build driver, hare, and the compiler, harec, are available under the GPL 3.0 (but not any later version). This permits free use and redistribution, but any changes to it require you to share the derivative work under the terms of the GPL. It is stricter than the MPL; if you link to the compiler or build driver code from a third-party program it will require you to release the third-party code as well.

In short, you can write programs in Hare which use the standard library and distribute those programs under any terms you wish. However, if you modify Hare itself, you must share your changes as well.

The Hare specification is licensed much more strictly: CC-BY-ND. This license allows free redistribution of the document, but prohibits derivative works entirely. The purpose is to prevent the proliferation of vendor extensions to the language itself. However, these terms only apply to the specification itself: if you use the specification to write an implementation of the Hare language, you are not restricted in how you license your work.