REPL

Read. Eval. Print. Loop.

This feature is in active development. Details may change. We're delighted to get feedback as the REPL feature evolves.

Getting started

Bring the power of Jupyter kernels to your editor! The built-in REPL for Zed allows you to run code interactively in your editor similarly to a notebook with your own text files.

To start using the REPL, add the following to your Zed settings.json:

{
  "jupyter": {
    "enabled": true
  }
}

Installation

Zed supports running code in multiple languages. To get started, you need to install a kernel for the language you want to use.

Currently supported languages:

Python (ipykernel)
TypeScript (Deno)

Once installed, you can start using the REPL in the respective language files, or other places those languages are supported, such as Markdown.

Using the REPL

To start the REPL, open a file with the language you want to use and use the repl: run command (defaults to CMD + Enter on macOS). You can also click on the REPL icon in the toolbar.

The repl: run command will be executed on your selection(s), and the result will be displayed below the selection.

Outputs can be cleared with the repl: clear outputs command, or from the REPL menu in the toolbar.

Changing which kernel is used per language {#changing-kernels}

Assign kernels by name to languages in your settings.json.

{
  "jupyter": {
    "kernels": {
      "python": "conda-env",
      "typescript": "deno-debug"
    }
  }
}

If you have jupyter installed, you can run juptyer kernelspec list to see the available kernels. Note that only

$ jupyter kernelspec list
Available kernels:
  ark                   /Users/z/Library/Jupyter/kernels/ark
  conda-base            /Users/z/Library/Jupyter/kernels/conda-base
  deno                  /Users/z/Library/Jupyter/kernels/deno
  deno-debug            /Users/z/Library/Jupyter/kernels/deno-debug
  deno-release          /Users/z/Library/Jupyter/kernels/deno-release
  python-chatlab-dev    /Users/z/Library/Jupyter/kernels/python-chatlab-dev
  python3               /Users/z/Library/Jupyter/kernels/python3
  ruby                  /Users/z/Library/Jupyter/kernels/ruby
  rust                  /Users/z/Library/Jupyter/kernels/rust
```

Note: Zed will not find kernels nested within your Python `sys.prefix`, shown here as `/Users/z/.pyenv/versions/miniconda3-latest/`.

```
$ jupyter kernelspec list
Available kernels:
  conda-base            /Users/z/Library/Jupyter/kernels/conda-base
  python3               /Users/z/.pyenv/versions/miniconda3-latest/share/jupyter/kernels/python3
```

## Language specific instructions

### Python {#python}

#### Global environment

<div class="warning">

On MacOS, your system Python will _not_ work. Either set up [pyenv](https://github.com/pyenv/pyenv?tab=readme-ov-file#installation) or use a virtual environment.

</div>


To setup your current python to have an available kernel, run:

```
pip install ipykernel
python -m ipykernel install --user
```

#### Conda Environment

```
source activate myenv
conda install ipykernel
python -m ipykernel install --user --name myenv --display-name "Python (myenv)"
```


#### Virtualenv with pip

```
source activate myenv
pip install ipykernel
python -m ipykernel install --user --name myenv --display-name "Python (myenv)"
```

### Typescript: Deno {#typescript-deno}

[Install Deno](https://docs.deno.com/runtime/manual/getting_started/installation/) and then install the Deno jupyter kernel:

```
deno jupyter --unstable --install
```

### Other languages

The following languages and kernels are also supported. You can help us out by expanding their installation instructions and configuration:

* [Julia (IJulia)](https://github.com/JuliaLang/IJulia.jl)
* R
  - [Ark Kernel](https://github.com/posit-dev/ark) - via Positron, formerly RStudio
  - [Xeus-R](https://github.com/jupyter-xeus/xeus-r)
* [Scala (almond)](https://almond.sh/docs/quick-start-install)

repl.md

REPL

Getting started

Installation

Using the REPL

Changing which kernel is used per language {#changing-kernels}