Counterclockwise is an Eclipse plugin that allows developers to write Clojure code within the Eclipse IDE. It provides features like syntax highlighting, structural editing commands, code completion, and interactive development through a REPL. Future plans for Counterclockwise include improving the editor, project management, REPL, refactoring support, and debugger integration. It is an open source project maintained by volunteers and is available through the Eclipse marketplace.

1. State of Counterclockwise:
Past, Present and Future
http://bit.ly/counterclockwise
by Laurent Petit
@laurentpetit
first.clojure-conj.org - 2010/10/22

2. Agenda
● Presentations / Intro
● History / Figures
● Installation
● Features / quick demos
● Future
● Credits
● Q & A

3. Presentations 1/2
● Me
● Laurent Petit, french
● Fond of Clojure since Q2 2008
● Involved in Counterclockwise since Q4 2008

4. Presentations 2/2
● Eclipse
● multi-language software development environment
● Primary target language/platform: Java/JVM
● Eclipse Foundation claims “millions” of users,
worldwide
● Counterclockwise
● An Eclipse extension for managing Clojure-based
projects
● License : EPL
● “ccw” for short

5. Intro 1/2
● Counterclockwise is an Eclipse plugin helping
developers write Clojure code
● Why an Eclipse plugin ?
● Targetting a large base of java developers
● Driving forces : writing Eclipse plugins both at work
& at home !
● Want Clojure for my next paid java project !

8. Intro 2/2
● Installing Counterclockwise and starting
testing/developing in clojure is really just a
matter of minutes!

9. Intro 2/2
● Installing Counterclockwise and starting
testing/developing in clojure is really just a
matter of minutes!
● Ease of installation = maximize a good first
impression with the language (like it or not !)

10. Intro 2/2
● Installing Counterclockwise and starting
testing/developing in clojure is really just a
matter of minutes!
● Ease of installation = maximize a good first
impression with the language (like it or not !)
● No-brainer integration into Eclipse java users'
toolset
– Parens will already feel UFOs to them, let the IDE get out
of their way and help them concentrate on the concepts

11. Intro 2/2
● Installing Counterclockwise and starting
testing/developing in clojure is really just a matter of
minutes!
● Ease of installation = maximize a good first impression
with the language (like it or not !)
● No-brainer integration into Eclipse java users' toolset
– Parens will feel alien enough to new users, let the IDE get out
of their way and help them concentrate on the concepts
● But should provide same interactive “dynamic”
experience

12. Agenda
● Presentations / Intro
● History / Figures
● Installation
● Features / quick demos
● Future
● Credits
● Q & A

13. History
● Started in 2008
● By Casey Marshall, code name “clojure-dev”
● Joined on October 2008
● Casey left the team early 2009 ...
● … got the “de-facto” leadership since then

14. Figures (google analytics)
Homepage – 2000 views per month
● Since March 1, 2010:
● ~ 4000 different visitors
– 800-900 average different visitors per month
● ~2000 homepage views per month
● ~2000 documentation page views per month

15. Agenda
● Presentations / Intro
● History / Figures
● Installation
● Features / quick demos
● Future
● Credits
● Q & A

16. Installation
● Super easy
● Use Eclipse 3.6 Helios' Market place
– Menu Help > Eclipse Market Place
– search for “clojure” & click
● Super fast
● 6 Mb download

17. Agenda
● Presentations / Intro
● History / Figures
● Installation
● Features / quick demos
● Future
● Credits
● Q & A

18. Editor features 1/2
● Syntactic coloration (stable)
● Strictly speaking, “token-based” coloration
● “rainbow” parens (and higlight, and jump to/from)
● Around the corner: true syntactic coloration (full use of parser's info)
● Structural edition commands (stable)
● based on emac's paredit.el (~ 80% commands currently ported)
● Totally reusable outside Eclipse context (pure clojure)
● Jump to definition (stable)
● Only to clojure global vars for now on ...
● Auto-indentation (stable)
● Predictable behaviour with & without support of dynamic environment
● But judged “too simple” by increasing number of users ...

19. Editor features 2/2
● Code completion (incomplete)
● Clojure top level vars
● Java
– Clojure is “backward”
– full search in the project's classpath)
– → slow !
● REPL interaction commands (stable)
● Documentation hover (around the corner)
● Code Outline (unstable)
● Missing: formatting, macro-expansion

20. Editor demo
● Structural edition modes
● Default mode – does not break habit
● Strict mode – mixed free/guided mode
● Underused structural edition commands
● Both modes
– Structure-based selection
– Raise over parent
– Split / Join
● Strict mode only
– Easy wrapping

21. Project management feature
● Compliant with Eclipse's notion of project
● Project “natures” : composable with JDT nature,
etc.
● “Running the project” uses “enhanced” java-
nature-based “launch configuration”
● Enabled to quickly provide out-of-the-box
interactivity

22. Interactive Dev feature1/2
● REPL' state of the art (v0.0.64)
● Based on the Java nature of the project
– Uses the project's classpath
– Same configuration tabs as the java's
● But limited in scope ...
– Forces the project to start with a stdin/stdout-based REPL class
(e.g. clojure.main or clojure.contrib.repl-ln)
– Not possible to work with web projects (WTP), GWT projects,
Eclipse projects (PDE)
● … and in features
– Plain text edition (no colors, no user assistance)
– No history

23. Interactive Dev feature 2/2
● Brand new REPL around the corner !
● Based on cemerick's nREPL client/server REPL library
● And on cemerick's rework of the Graphical REPLView !
● Connection to any JVM running a nREPL client
● No more need for special “launch configuration”
● => composable with projects of any kind (Web WTP, GWT, AppEngine,
etc.)
● Rich set of feature for the REPL View
● Shares source code editor featureset: colors, structural edition, code
completion (wip), navigation commands, etc.
● Colorized logs
● Recall previously entered commands (wip)
● Multiline (with auto-indentation!) command area

24. Interactive Dev demo
● “launch” your project
● auto-reload-on-save enabled or disabled
– Agile feature design at work ! :-)
● Exclusivity: new REPL View !
● Same feature set as editor
● Receive code from the editor
● Namespace browser
● Embedded search engine
● Click to jump to definition

25. Debugger feature
● Features
● Place breakpoints in clojure code
● Leverage the classic Eclipse integrated java
debugger
● Still a little bit unstable
● Future work
● Does not (yet) filter frames related to the internals
of clojure (clojure.lang.*)
● Integration with George Jahad's CDT debugger

26. Agenda
● Presentations / Intro
● History / Figures
● Installation
● Features / quick demos
● Future
● Credits
● Q & A

27. Future – features around the corner
● Editor
● Jump to definition (java)
● Documentation hover (clojure & java)
● True syntax-based coloration (locals, etc.)
● Project management
● More “orthogonality” with underlying “project nature” (pure
java, GWT, WTP, AppEngine, Eclipse RCP, etc.)
● REPL
● Port features of the editor
● And then … towards “graphical REPL” (ability to display
“binary” return values as images, HTML, charts, etc.)

28. Future – other features
● Refactoring features
● Integration of tcrayford's clojure-refactoring project
● Hopefully bidirectional java ↔ clojure
● Debugging features
● Integration with George Jahad's Clojure Debugging
Toolkit (CDT)

29. Future – “dream-about” features
● More “warnings” than what the compiler has to offer
● Help enforcing conventions
● Help detect potential bugs (more than one statement
inside dosync, local same name as global, etc., etc.)
● → No hurry, 'cause “cinc” may be a game changer ...
● “AI-like” User suggestions
● Analyse user's habits through heuristics (and occurrence)
● Non-invasive (hard part !) suggestions

30. Future - Miscellaneous
● Introduction of Contributor Agreement
● Better juridical protection for project's code
● Better protection of sponsor's rights on project “as a whole”
● copy&paste of Clojure's one, just names changed
● Switch to “semantic versioning”
● “embedded” REPL for ccw own's development
● Open the door to more contributors
● devs:
– mvn based build process
– Continuous integration
● users:
– Update Sites for “beta” versions as well as “stable” version
– Opening the plugin to user contributions (in clojure, of course)

31. Agenda
● Presentations / Intro
● History / Figures
● Installation
● Features / quick demos
● Future
● Credits
● Q & A

32. Share, ...
● Past & current contributors
● Casey Marshall (first versions of ccw)
● Stephan Müehlstraßer (preference pages, online
help, labrepl support)
● Christophe Grand (Debug breakpoints)
● Manuel Woelker (Source code outline)
● Miaubiz, clooney (editor commands:navigate to
definition, etc.)
● Nicolas Lambert (Outline commands)
● Chas Emerick (integration with nREPL, REPLView)

33. … reuse,
● vimClojure (@kotarak): code completion
● parsley (@cgrand): source code parser
● clojure.osgi (@aav): clojure+OSGi love story
● nREPL (@cemerick): REPL client/server library

34. … give back.
● Structural Editor
● paredit.clj (github)
● Clojure Grammar
● ccw.parsers.clojure (github, wip, no rush please)

35. Where to find it
● Google code home page
● http://code.google.com/p/counterclockwise/
● Google groups
● Users : http://groups.google.com/group/clojuredev-
users (66 members)
● Devs :
http://groups.google.com/group/clojuredev-devel
(37 members)

36. Agenda
● Presentations / Intro
● History / Figures
● Installation
● Features / quick demos
● Future
● Credits
● Q & A

37. Thanks for attending!
(can you wake up your neighbor pliz ?)