# roc_ls

This is a rudimentary language server for supporting basic editor usage in Roc.

Support for the following LSP features are provided:




- Inline diagnostics
- Hover support to get types of values
- Go-to-definition
  - <details><summary>Example</summary>

    https://github.com/ayazhafiz/roc/assets/20735482/23a57d06-5b70-46f2-b0c4-5836eaec669b

    </details>
  - Note that go-to-definition for the builtins does not yet work.
  - Go-to-definition for abilities resolves to their specialization, if one exists.
    - <details><summary>Example</summary>

      https://github.com/ayazhafiz/roc/assets/20735482/1ba98bf9-518b-4c47-b606-a6ce6767566f

      </details>
- Formatting Roc files on save
  - <details><summary>Example</summary>

    https://github.com/ayazhafiz/roc/assets/20735482/fbbe4bc1-64af-4c7d-b633-d7761906df11

    </details>

Semantic highlighting will also be added soon. Additional features require
changes to the compiler infrastructure that are not yet available.

Note that the language server is a bit naive:
- If you make a change in a dependency, you'll need to also make a change in
    the dependents' files for the changes to be picked up
- The language server will only operate on changes that are also reflected on
    disk (so save often)

## Installing

At this time, only from-source installations of the binary are supported.

Follow the [installation from source](https://github.com/roc-lang/roc/tree/main/getting_started#installation) instructions. Then run

```
cargo build -p roc_lang_srv --release
```

which will give you a language server binary at

```
target/release/roc_ls
```

### Configuring in your editor

Please follow your editor's language server implementation's documentation to see how custom language servers should be configured.

#### [coc.nvim](https://github.com/neoclide/coc.nvim)

Add the following to your coc JSON configuration file:

```
{
  "languageserver": {
    "roc": {
      "command": "<path to binary folder>/roc_ls",
      "filetypes": ["roc"]
    }
  }
}
```

If you're using coc.nvim and want to use the configuration above, be sure to also instruct your vim that `*.roc` files have roc filetype.

## Debug

If you want to debug the server, use [debug_server.sh](./debug_server.sh)
instead of the direct binary.