An implementation of a Lisp which is suspiciously similar to Clojure.

Download a tarball for your platform—Linux or Mac OS X—extract it and start the REPL with:

./psota

If you have rlwrap installed you can augment the REPL with a history and readline keybindings by invoking it with:

rlwrap ./psota

You can execute an arbitrary file by passing its name as an argument:

./psota test.clj

Instructions for building Psota from source can be found in one of following sections.

tl;dr: I want the Clojure REPL to start up faster than I can pronounce psota.

The goal of this project is to implement a language resembling Clojure as closely as possible while guaranteeing:

• fast start up time of the VM,
• ability to use it for command line scripting,
• no ahead-of-time compilation of executed code,
• compatibility with all features which aren't dependant on the host platform,
• a REPL as powerful as in the original language, and
• reasonable performance (quite vague, isn't it?).

Let's be reasonable. There aren't many ways of beating JVM as a host platform. Realistically speaking,

• you can't beat its performance,
• you can't beat the breadth of its ecosystem
• you can't beat its tooling, but
• you can start up faster.

Let's do it.

You need Python 2 and sources of PyPy. PyPy is expected to be located in ../pypy. If it's elsewhere specify path to it using PYPYPATH environment variable.

To build an executable and run a REPL invoke

make repl-O2

An executable with a JIT compiler can be built and run by executing

make repl-Ojit

If you don't mind very poor performance Psota can be run without the compilation step by invoking

make repl

None were asked! Feel free to fill this gap by contacting me over e-mail or at @janstepien. There's also the #psota IRC channel on freenode. I'd love to hear from you.

Unless otherwise stated, code in this repository is licensed under following terms.

Copyright (c) 2013–2014 Jan Stępień

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.