Run the REPL

The REPL (Read, Evaluate, Print Loop) is the runtime environment for Clojure. The REPL evaluates your code and returns a result. You can evaluate a whole project or just a single expression. An expression is Clojure code contained within (). You can also evaluate symbols, numbers, strings, etc.

Note From the root of your project directory, run the following command 

  1. lein repl

Check the REPL works with some simple maths. At the REPL prompt, user=>, enter the following code and press the return key

  1. (+ 1 2 3)

The Clojure REPL should return the value 6

Run the REPL - 图1

Hint The user=> prompt is telling you what namespace the REPL is currently running in, by default this is user. The => are characters representing the prompt, just like you get on the command line.

If you need to close the REPL at any point, type (exit)