# KCL

Our language for defining geometry and working with our Geometry Engine efficiently. Short for KittyCAD Language, named after our Design API.

## Contributing a standard library function

We've built a lot of tooling to make contributing to KCL easier. If you are interested in contributing a new standard library function to KCL, here is the rough process:

1. Open just the wasm-lib folder in your editor of choice. VS Code, for example, struggles to run rust-analyzer on the entire modeling-app directory because it's such a turducken of TS and Rust code.
2. Find the definition for similar standard library functions in `./kcl/src/std` and place your new one near it or in the same category file.
3. Add your new code. A new standard library function consists of:
4. A `pub async` of the actual standard library function in Rust
5. A doc comment block containing at least one example using your new standard library function (the Rust compiler will error if you don't provide an example our teammates are dope)
6. A `stdlib` macro providing the name that will need to be written by KCL users to use the function (this is usually a camelCase version of your Rust implementation, which is named with snake_case)
7. An inner function that is published only to the crate
8. Add your new standard library function to [the long list of CORE_FNS in mod.rs](https://github.com/KittyCAD/modeling-app/blob/main/src/wasm-lib/kcl/src/std/mod.rs#L42)
9. Get a production Zoo dev token and run `export KITTYCAD_API_TOKEN=your-token-here` in a terminal
10. Run `TWENTY_TWENTY=overwrite cargo nextest run --workspace --no-fail-fast` to take snapshot tests of your example code running in the engine
11. Run `just redo-kcl-stdlib-docs` to generate new Markdown documentation for your function that will be used [to generate docs on our website](https://zoo.dev/docs/kcl).
12. Create a PR in GitHub.

## Bumping the version

If you bump the version of kcl-lib and push it to crates, be sure to update the repos we own that use it as well. These are:

- [kcl.py](https://github.com/kittycad/kcl.py)
- [kcl-lsp](https://github.com/kittycad/kcl-lsp)
- [cli](https://github.com/kittycad/cli)
