Errpy: An Error Recovering Rust Python Parser

This is a new project to provide an error-recovering Python parser, implemented in Rust based on tree-sitter. Our short-term goal is to use it in the pyre type checker, in order to provide better IDE features.

License

Errpy is licensed under the MIT license.

Building

Errpy depends upon the following:

• Ocaml
• Dune
• Rust
• Cargo

Platform

ERRPY is verified as being buildable on Linux on OCaml 4.14.0

Installing Ocaml and Dune

Install opam and run opam switch install "4.14.0"

Usage

It is recommended to use dune as your build system. To use errpy in your dune project, you can add errpy to the libraries stanza in your dune file. For example,

(library
  (name mylib)
  (libraries errpy))

For local development

If you want to test your changes to errpy locally and use them in another OCaml project (.e.g. Pyre) you can try the following,

First clone the repo with: $ git clone https://github.com/facebook/errpy.git

Or use $ git clone --branch release https://github.com/facebook/errpy.git if you’re operating within an offline rust enviroment.

... make the required changed ...
$ cd errpy
$ dune build @install          # Build the errpy library
$ dune test                    # Run tests
$ opam pin add errpy . -n      # pin opam to errpy
$ opam install errpy --verbose # install local build as errpy in opam

Formatting

When making Ocaml changes you can run ocamlformat in order to ensure code is formatted in a conistent manner. This is invoked as follows:

$ dune build @fmt
$ dune promote