Erlang Language Platform (ELP)

Description

ELP integrates Erlang into modern IDEs via the language server protocol.

ELP was inspired by rust-analyzer.

Terms of Use

You are free to copy, modify, and distribute ELP with attribution under the terms of the Apache-2.0 and MIT licences. See LICENCE-APACHE and LICENCE-MIT for details.

Prerequisites

VS Code

Coming soon.

Emacs

1. Download the appropriate elp executable from https://github.com/WhatsApp/erlang-language-platform/releases, and make sure it is on your $PATH.
2. Add the following to your emacs init file

(use-package lsp-mode
  :custom
  (lsp-semantic-tokens-enable t)

  :config
  ;; Enable LSP automatically for Erlang files
  (add-hook 'erlang-mode-hook #'lsp)

  ;; ELP, added as priority 0 (> -1) so takes priority over the built-in one
  (lsp-register-client
   (make-lsp-client :new-connection (lsp-stdio-connection '("elp" "server"))
                    :major-modes '(erlang-mode)
                    :priority 0
                    :server-id 'erlang-language-platform))
  )

How to use ELP

Using it with rebar3 projects

1. Use OTP 25

2. Download the elp binary for your system from https://github.com/WhatsApp/erlang-language-platform/releases

   On Mac you will probably get the following message when trying to run the executable the first time: "elp cannot be opened because the developer cannot be verified.". To solve this, go to Preferences > Security and Privacy and add an exception. Alternatively, you can build elp from source.

3. Add eqwalizer_support dependency and eqwalizer_rebar3 plugin to your rebar3 project definition (see below)

4. From the project directory run:

• elp eqwalize <module> to type-check a single module
• elp eqwalize-all to type-check all src modules in the project

Adding eqwalizer_support and eqwalizer_rebar3:

{deps, [
  {eqwalizer_support,
    {git_subdir,
        "https://github.com/whatsapp/eqwalizer.git",
        {branch, "main"},
        "eqwalizer_support"}}
]}.

{project_plugins, [
  {eqwalizer_rebar3,
    {git_subdir,
        "https://github.com/whatsapp/eqwalizer.git",
        {branch, "main"},
        "eqwalizer_rebar3"}}
]}.

References

• rust-analyzer

Contributing

• CONTRIBUTING.md: Provides an overview of how to contribute changes to ELP (e.g., diffs, testing, etc)

FAQ

Please refer to the FAQ document for answers to some common questions, including:

• What's the difference between ELP and Erlang LS?
• Why not extend Erlang LS, rather than creating a new tool?
• Why is ELP implemented in Rust, rather than Erlang?

License

erlang-language-platform is dual-licensed

• Apache.
• MIT.