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 ?)