/sml-redprl

Decisively Smash the Formalist Clique!—The People's Refinement Logic

Primary LanguageStandard MLMIT LicenseMIT

PRL: We Can Prove It

(image courtesy of @tranngocma)

What is RedPRL?

RedPRL is the People's Refinement Logic, a next-generation homage to Nuprl; RedPRL was preceeded by JonPRL, written by Jon Sterling, Danny Gratzer and Vincent Rahli.

The purpose of RedPRL is to consolidate several advances in refinement logics and type theory, including:

  • a multi-sorted version of abstract binding trees
  • support for nominal abstraction and unguessable atoms
  • a dependent version of the LCF apparatus to support refinement rules whose premises depend on each other's evidence
  • computational cubical type theory

Literature and background on RedPRL

RedPRL is (becoming) a proof assistant for Computational Cubical Type Theory, as described by Angiuli and Harper in Computational Higher Type Theory II: Dependent Cubical Realizability. The syntactic framework is described in a note by Jon Sterling called Aspects of Cubical Type Theory, and is inspired by Harper's "abstract binding trees" (Harper, Practical Foundations for Programming Languages; Sterling & Morrison, Syntax and Semantics of Abstract Binding Trees).

What is this repository?

This is the repository for the nascent development of RedPRL. RedPRL is an experiment which is constantly changing; we do not yet have strong documentation, but we have an IRC channel on Freenode (#redprl) where we encourage anyone to ask any question, no matter how silly it may seem.

How do I build it?

First, fetch all submodules. If you are cloning for the first time, use

git clone --recursive git@github.com:RedPRL/sml-redprl.git

If you have already cloned, then be sure to make sure all submodules are up to date, as follows:

git submodule update --init --recursive

Next, make sure that you have the MLton compiler for Standard ML installed. Then, simply run

./script/mlton.sh

Then, a binary will be placed in ./bin/redprl, which you may run as follows

./bin/redprl test/test.prl

Editor Support: Emacs

We have support for interactive RedPRL development in Emacs.

MELPA

The Emacs mode is a part of this repository. Additionally, it is available in MELPA.

The easiest way to install the package is from MELPA, using their getting started instructions. The package is named redprl. It will probably be necessary to set the customization variable redprl-command to the path to the redprl binary.

When redprl-mode is installed, files ending in .prl will automatically open in the mode. If they do not, run M-x redprl-mode. The mode supports the following features:

  • Press C-c C-l to send the current development to RedPRL.

  • Imenu (or wrappers such as helm-imenu) can be used to jump to definitions in the buffer.

  • Completion is supported for names of declarations in the current buffer.

  • Flycheck is also supported, and can be used in lieu of C-c C-l if you like. Be sure that either the redprl executable is in your path, or set flycheck-redprl-executable in your own Emacs configuration.

Contributing

If you'd like to help, the best place to start are issues with the following labels:

We follow the issue labels used by Rust which are described in detail here.

If you find something you want to work on, please leave a comment so that others can coordinate their efforts with you. Also, please don't hesitate to open a new issue if you have feedback of any kind.

The above text is stolen from Yggdrasil.