nvim-treesitter-context/CONTRIBUTING.md

## Adding support for other languages

### Composing `context.scm` queries

To add support for another language, simply add a `context.scm` file under
`queries/[LANG]`.

Queries specify the `@context` capture which specifies the first line of a node
will be used for the context.

Here is a basic example for C:

```query
(function_definition) @context
(for_statement) @context
(if_statement) @context
(while_statement) @context
(do_statement) @context
```

You can look at a node names of a tree using `:InspectTree`.

Additionally an optional `@context.end` capture can also be specified. When
provided, the text from the start of the `@context` capture to the start of
`@context.end` capture (exclusive) will be used for the context and joined into
a single line.

Here's what that looks like for C:

```query
(if_statement consequence: (_ (_) @context.end)) @context
```

This query specifies that everything from the `if` keyword up-to the first
statement (exclusive) should be used for the context. This is useful when an
if-statement spans multiple lines.

### Committing your changes

Your commit messages should follow the [Conventional Commits specification](https://conventionalcommits.org).

Good:

```
feat(lua): added lua support
```

Bad:

```
added lua support
```

> You can do `git commit --amend` followed by `git push --force` if you made a mistake.

### Raising a pull request

A pull request for supporting a new language requires:

1. Adding `queries/[LANG]/context.scm` as explained in the previous section.

2. Adding `test/lang/test.[LANG]` or `test/lang/test.[LANG].[EXT]` with code examples the `context.scm` is designed to support.
  - These test files use custom comment directives to annotate what lines should be a context. It has the format.

    ```c
    // {{TEST}} -- mark start of test

    int main() { // {{CONTEXT}} -- mark line as a context


    // {{CURSOR}}  -- where cursor needs to be for contexts to be shown.

    }
    ```

    See `test/lang/test.c` for examples.

3. Updating `README.md` to mark `[LANG]` as supported.