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Getting Started#

Depending on wether you want to just start a Clojure REPL or you have a project you want to work with, getting started looks similar but a bit different. Regardless, you need to first:

Install VS Code and Calva#

  1. Downloading VS Code and run the installer.
  2. Install Calva. The easiest way to do that is to start VS Code and search for Calva in the VS Code Extension pane, then click Install.

Say hello to Calva#

If you have a Clojure or ClojureScript project, you will be interested in how to get Calva connected to the REPL of your project. But before you run over there, you might want to familiarize yourself with Calva a bit, which you can do without a project.

The demo tells you about the command (and some about the Clojure Beginner's material that it makes available).

I am completely new to Clojure

The ”Getting Started” REPL below introduces you to Clojure as well as to Calva. You might however, not want to start with installing the right version of Java and such to run the guide. If so you should definitely check the Get Started with Clojure guide on this site.

Three clicks will have you running Calva in your browser with the REPL ready to serve.

I don't have Java installed

If you like, you can defer installing anything at all and still get started with Calva (not kidding).

See Get Started with Clojure.

There's a ”Getting Started” REPL#

If you are new to Calva, a good place to start is using the command Calva: Create a ”Getting Started” REPL. (You can open the command palette using the VS Code top menu by going to View -> Command Palette... or by running the associated keyboard shortcut for your OS.) Demo:

Command Palette Getting Started REPL

It will create a new project, open up a three files, and start and connect a REPL. The files are:

  • hello_repl.clj – The basics of how to evaluate code in Calva
  • hello_paredit.clj - A super brief intro to Calva structural editing
  • welcome_to_clojure.clj - The very basics of the Clojure language

Hello REPL

The only prerequisite here is that you have Java installed.

See the Getting Started with Clojure guide for a bit more about this feature.

Note

On Windows the Oracle Java installer sets Java up in some funny way so that the Getting Started REPL fails to start. We are figuring about workarounds for this, but for now, if you are on Windows, you will need to make VS Code have some other Java in the PATH of its environment for this feature to work. See this issue on the Calva repo for more on this, including any progress.

There are standalone ”ClojureScript Quick Start” REPLs#

Without creating a project structure or installing anything but Calva, you can start standalone ClojureScript REPLs both in a browser and for node:

  • Create a ClojureScript Quick Start Browser project
    • Opens the files core.cljs and index.html and starts the ClojureScript app, opening it in the browser.
  • Create a ClojureScript Quick Start Node project
    • Opens a file, core.cljs, and starts a nodejs REPL where it loads the file.

The browser REPL app looks like so:

ClojureScript Quick Start Browser REPL

You have a Project?#

If you are new to Calva, please consider the above option first. Then when it will be time to get Calva connected to the REPL of your project.

Clojure Resources#

If you are new to Clojure or ClojureScript altogether, please check out the guide material on the respective official sites:

There are also many great books on Clojure. Clojure for the Brave and True can be read for free online. It is a great resource for beginners.

Create a minimal Clojure project#

When you are more familiar with Calva, and want a standalone REPL, there is a separate command: Calva: Create a minimal Clojure project. It will ask for folder to create the project in, and open this project for you, connecting the REPL. The project is really minimal.

Dram - Where the Guides Live#

The command for starting the Getting Started REPL will download the files from this repository. It is very much work in progress, and there is not even a finished Clojure Beginner's Guide there yet. When you run the command again, and from then on, you will get the option to download new files or keep using your existing. Downloading new ones will not overwrite your existing ones, because they will be downloaded to a new temp directory. You can find the directory easily using VS Codes context menu command for revealing a file in the Explorer/Finder.

One Last Thing#

Happy coding! ♥️