VSCode and Calva user guide

Open the VSCode editor and start a REPL for your project. Then add your Clojure project and connect to your REPL.

Open Project Folder in VSCode

Ctrl+k Ctrl+o to open the Folder that contains your project. Or using the menu File > Open Folder

Select the top level of the folder, e.g. playground and click OK

Add dependencies to project

Open the project.cj file and add the following dependencies

(defproject playground "0.1.0-SNAPSHOT"
  :dependencies [[org.clojure/clojure "1.8.0"]
                 [nrepl               "0.5.3"]
                 [cider/cider-nrepl   "0.20.0"]])

Run a REPL for the project using Leiningen.

Ctrl+` toggles open the VSCode Integrated terminal. Or open your operating system terminal.

Windows GitBash users

Configure the Atom internal terminal to use the GitBash shell.

In the terminal, change to the folder than contains your project, e.g. cd projects/clojure/playground

Type the command lein repl in the terminal.

Connecting to a Remote REPL from Calva

Ctrl+Alt+v c will open a command pop-up asking you to enter host and port. These details were shown when the REPL was run in the terminal.

In the bottom left of Atom, check the status of the nrepl connection. If you are connected, then the disconnected status should disappear

Developing your project

Once you have a running REPL, use these commands to help you develop your code.

Evaluate code	Keybinding	Description
Namespace	`Ctrl+Alt+v n`	Evaluate the current namespace and change namespace in REPL
All code in Namespace	`Ctrl+Alt+v alt+n`	Evaluate all the code in current namespace
Outer expression	`Ctrl+Alt+v SPACE`	Show the result of the top level expression
Expression	`Ctrl+Alt+v e`	Show the result of the current expression
Expression (send to REPL)	`Ctrl+Alt+v alt+e`	Send expression to the REPL and evaluate
Pretty print	`Ctrl+Alt+v p`	Print expression so its easier to read
Replace expression	`Ctrl+Alt+v r`	Replace the expression with its result
In the REPL	`shift+enter`	Code in the REPL window is evaluated

You can run tests from Calva too...

Tests to run	Keybinding	Description
All tests	`Ctrl+Alt+v Shift+t`	Run all tests in the project
Current Namespace tests	`Ctrl+Alt+v t`	Run all tests for the current namespace
Re-run failing tests	`Ctrl+Alt+v Ctrl+t`	Run all tests for the current namespace

REPL history

The REPL maintains a history of the code typed in and can be navigated by using the up and down arrow keys.

Commenting / uncommenting code

Type ;; at the start of a line to comment out the whole line.

Comment keybindings ?

Increase / decrease font size

Ctrl + and Ctrl - will increase and decrease the size of the whole editor.

Structured editing - Paredit

Once you get the basics of Clojure development, you can try structural editing which is a way to refactor you code without breaking the structure of Clojure. Structural editing ensures you dont have uneven parentheses, (), [], {}, etc.

Please look at the documentation for Calva Paredit to make use of Structural editing.

VS Code - Calva