Pre-requisites

• Java 6 (for running Eclipse, you can still use Java 5 for your projects)

Install Eclipse

(If you do not have Eclipse installed, or you want to make isolated tests of the Clojure plugin for Eclipse)

• Grab the Eclipse ZIP file from http://www.eclipse.org/downloads . If you do not know which "package" to get, pick the "Eclipse IDE for Java Developers" one since it ships out of the box with Git support
• Unzip it somewhere. The executable is eclipse (linux) or eclipse.exe (windows) located in the eclipse/ directory created by the unzip operation
• The first time Eclipse is run, it will ask you for a location on your disk where eclipse will put its metadata and will create new projects by default.

Install Counterclockwise (the Clojure plugin for Eclipse)

(Counterclockwise, CCW for short, is the Clojure plugin for Eclipse)

You install it via the “software update center”, that is:

• Menu Help > Install new software…
• Paste the following Counterclockwise url in the “Work with:” textbox: http://ccw.cgrand.net/updatesite/ , Hit Enter
• Select counterclockwise, verify the “Contact all update sites during …” chekbox is checked, click next, accept licence, etc., restart Eclipse
• Go to menu Window > Reset Perspective ... this will reset the way the views are layout, and also place correctly the views contributed by Counterclockwise (the Namespace Browser view, placed "behind" the code outline view)

Test the install

Create and run a simple Clojure project ("Hello Betty")

• Open the Java perspective
  • Window > Open Perspective > Java (a perspective is a predefined layout of views, suitable for a particular type of development)
• Create a Clojure project
  
  • With Leiningen Project Wizard: File > New > Leiningen Project, name it myproject
  • The project is created using the "default" Leiningen Template, which creates a Clojure project with a predefined "myproject.core" namespace in src/myproject/core.clj
• Add a function definition to myproject.core:
  
  • Open src/myproject/core.clj, add the following at the end: (defn hello [who] (str "Hello " who " !")), save the file
• Run the project:
  
  • With file src/myproject/core.clj open, Hit Ctrl+Alt+S (Cmd+Alt+S on MacOS). This sends the whole file's code to the REPL (and also takes care of starting a REPL for the project if none is currently started)
• Switch to the REPL in the namespace of your file:
  
  • Hit Ctrl+Alt+N (Cmd+Alt+N on MacOS). Alternatively, just click on the bottom of the REPL inside the "text input area"

• Call your function (Hit Enter to send the expression if the cursor is at the end, or hit Ctrl+Enter / Cmd+Enter if the cursor is not at the end of the text):

  > 1:1 helloworld=> (hello "Betty") [Ctrl+Enter] > "Hello Betty !"