Last night Roy and I went to the the Ottawa Carleton Smalltalk Users Group meeting, where the presentation was "Smalltalk in Eclipse: How to build your favorite language IDE" by John Duimovich of IBM. It was for SmallTalk developers so John thought we would all know Smalltalk and not much about Eclipse. There were a few of us where the opposite was true. :) But that was still OK, I still learned a lot and Eclipse and SmallTalk.

Unfortunately it looks like a Smalltalk IDE in Eclipse from IBM won't be coming out for a while. One of the reasons is that IBM is wary of releasing new code as open source after the whole SCO mess started going down, which is fair enough. That code included the Eclipse plugins themselves, a Smalltalk library and IBM's Smalltalk VM (which he mentioned they would have to release as binary probably). Another is they already have another Smalltalk IDE, developed by the same company (OTI, bought by IBM) that ended up writing Eclipse. There doesn't seem to be much demand for Smalltalk in Eclipse either, so without a business case the effort might have to be more community-driven. It seemed like John was testing the waters with these Smalltalk developers and although there were no boisterous bouts of spontaneous applause they seemed impressed by Eclipse's features.

The talk was based on a presentation John just made at EclipseCON 2004 less than a month ago and then he demo'd his Smalltalk Eclipse IDE. It is language aware, constructing a DOM out of the Smalltalk code and letting the user see it in the outline view as well as code completion.

The difficulty of making an Eclipse IDE for Smalltalk was the fact that Smalltalks don't use files, they use an image. The analogy of an image being like an old carpet was pretty good -- it catches everything that walks over it -- all of your edits. So he had to make a system where an image could be reconstructed and then saved, split the Smalltalk source into files on the file system and create equivalents to the Java tools java, javac and javaw. So it appears to me, though I am new to Smalltalk, that this wouldn't be completely like a traditional Smalltalk IDE -- it's morphed to fit into the Eclipse paradigm.

Part of the talk included a very interesting tangent on a concept called "doits" (pronounced "do its", not "doyts"). I'm not sure if it only applied to the Smalltalk Eclipse IDE or Eclipse in general though. The idea is to put a simple scripting language in Eclipse that you can use to perform quick tasks in the IDE. The example doit he gave was if someone else found a bug they could attach a doit to the bug report that would download the project from CVS, compile it and then highlight the line that refers to the bug. A scriptable IDE sounds really cool indeed. I don't think he mentioned a possible language it would use if they made it though. Maybe python?

In the future after a complete Smalltalk IDE was made the next step might be to let people write Eclipse plugins in Smalltalk. Obviously this would require Java (the language Eclipse is written in) and Smalltalk to play nicely with each other. The Eclipse developers have been down this path before though when they made Visual Age for Java, except it was the other way around. VAJava is written in Smalltalk.

So in that situation the Java and Smalltalk VMs would be going at the same time. The conversation at the talk then went into Microsoft and the .NET Common Language Runtime (CLR) and how it was able to excute all of these different languages in the same runtime. Would something like this be possible for Java and Smalltalk? John said that it was done before and called the Universal VM but it wasn't an ideal solution because the UVM didn't support C++ from the beginning. He also mentioned that Microsoft's work on the CLR may have started because they heard about the UVM and thought they better make something to compete with it! So now Microsoft has the CLR and the rest of us have, well, nothing ... unless you count Mono and I don't because Java doesn't run on Mono.

As someone new to Smalltalk I'm a little worried about all of the dialects of the language. Do they fragment the Smalltalk community? It seems as though they would make developing a Smalltalk IDE in Eclipse harder. John mentioned that for his Smalltalk Eclipse IDE he would like the various Smalltalks to agree on an output format for the images and such. What if this doesn't happen easily? It could slow down development more.

At any rate, Smalltalk is interesting stuff and I'll probably be hacking on it soon even though the Eclipse IDE isn't coming out for a while. Any recommendations for a good (and free) Smalltalk IDE for a Java developer slash Smalltalk noob like myself?