CodeRage II, Day 3, My DSL Talk

In the third day of CodeRage II, I gave my talk on Domain Specific Languages in Delphi.

It is day 3 at CodeRage II, CodeGear's second online conference. I've just done the Q&A session for my last talk, on Domain Specific Languages in Delphi. This is not a very popular topic, I mean it is quite a new approach in the Delphi community, although some people with DSL experience turned out to attend. Good. Overall, at my talk there were about 150 people, less then yesterday. There were fewer questions, but that's good as it was the first time I gave this talk, and I don't consider myself an expert in this area.

As yesterday, the source code is available to all at www.marcocantu.com/code/coderage/DslDelphi_Code.zip. Anders is busy fixing the Exhibit Hall link, that can be used to get to my site (among others) and buy a discounted version of Delphi 2007 Handbook. This offer is valid only until Friday.

I'm done speaking, but will stick around CodeRage. Actually tomorrow night I'll host my own vendor chat. Come there if you have any question, but also only for a chat. Yes, for us Europeans it is at midnight, not the best time of the day...

Its not surprising that a DSL talk would not draw a huge crowd. I would guess its a topic that a few would be passionate about but many would wonder "How can I use this?" I think its great that you are starting the conversation at least in the Delphi community. DSLs are nowhere near critical mass yet, but I feel their time is coming. Ruby sprang to prominence with the "killer demo" encapsulated in the Rails framework. For many people, Google Maps was the crucial killer app that allowed them to "get" AJAX. A couple of great demos that allow the DSL concept to crystallize is hopefully not too far in the future. Several of my coworkers that listened to your talk were wondering why the examples you presented were so far removed from the DSL-as-natural-language example. The soccer example was something like "The striker scored a header on a cross from the outside" The Delphi calendar examples presented two alternatives to "OOP code". My coworkers were left scratching their heads as to why the alternatives were any better. One said, "What's wrong with just using a 'with' statement!" My takeaway from your talk is that a DSL can offer a more intuitive syntax that may map more naturally to your current cognitive representation (what's already in your head). That leaves it about midway between OOP code and true natural language processing. Finally, I kept thinking about the Google Calendar interface during your talk. The help topic below gives several samples of statements that can be typed in to create a new calendar entry. http://www.google.com/support/calendar/bin/answer.py?answer=36604 I'm curious, how would you compare this Google Calendar feature to the topics you discussed?

I enjoyed your talk, but, as I commented yesterday, I was hoping for some more perspective on external DSLs. In my current application, I am relying a lot on configuring objects in my database as well as posting transactions against those objects using Excel files. Spreadsheets are a second language for a lot of PC users and provide an alternative for missing functionality in enterprise software. A spreadsheet is like a specialized thin client platform. And I think data arranged in a spreadsheet can fit the definition of a DSL. My approach to spreadsheet processing is pretty naive and I would be very interested in the perspective that someone with a larger breadth of knowledge would bring to the subject. After your talk, I found the online book on DSLs at Martin Fowler's website. I will read that and would be very interested in anything you do in this area.

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