In the Eclipse Europa simultaneous release, in addition to Eclipse 3.3, a number of other Eclipse projects were released, including Eclipse DLTK 0.9. DLTK, or Dynamic Language Tool Kit is a plugin designed to add support for dynamic languages within Eclipse.
Of particular interest is the Ruby support, as the popularity of Ruby has caused many Java IDEs to add Ruby support. Daniel Spiewak argues:
[M]aybe the best area I could envision improvement would be the DLTK Ruby project. DLTK Ruby is a phenomenally polished and stable Ruby IDE, but it lacks the feature richness of RDT (a subproject of Aptana).
Daniel also provides a good overview of the strengths and weaknesses of RDT when compared to DLTK:
RDT is a far more full-featured Ruby IDE with a ton of exciting and time-saving options. Once Chris gets all the bugs worked out of it, RDT will be a force to be reckoned with in the Ruby development world. DLTK seems to have taken a more conservative approach to its development (probably enforced by the imminent stable Europa release). DLTK's editor is polished, stable and very productive (you can't imagine how useful it is to have auto-insert of "end" statements). I guess the question is, will RDT spit-shine itself and find its stable feet first, or will DLTK overtake it in features, becoming the industry's de facto Ruby IDE?
Rails Support
DLTK does not contain tools specific to the Ruby on Rails framework such as support for server-launching, generators, .rhtml, etc. Some see these as 'missing features', but according to Andrey Platov, Project Lead for the DLTK, it's deliberate:
Probably I would upset a lot of Ruby developers but we['re] never going to support Ruby on Rails framework in the DLTK project. My strong vision [is] that such support shall be a subject of another project on top of Eclipse Webtools and DLTK Ruby (like Java [Enterprise Edition] Standard Tools subproject)
Extension
The dynamic language toolkit is designed with extension in mind: Andrey Platov indicates that the DLTK project is trying to create a language-independent layer that can be used by all dynamic language plugins.
In addition to the Ruby and Tcl support, Javascript and Python are already in experimental stages. And in development, there are projects to support Perl and Lua. CodeGear is also working on a Ruby IDE that extends the dynamic language tool kit, and has two DLTK committers on their team team.
Future Plans
Eclipse DLTK 1.0 is targeted for the Ganymede simultaneous release, and will focus on: "refactoring, code analysis, and advanced source code editing features like Quick Fixes" as well as "generic xUnit framework and concrete unit testing support for at least TCL, Ruby and Python". Andrey also speculates about supporting Groovy and JRuby in the next release.
You can read more about Eclipse, Ruby and the DLTK here on InfoQ.