Wednesday, 2 April 2008

Should you do DSLs alone when no-one is watching?

This post is sponsored by InfoQ and in particular this article.

The article gives a summary of a blog post from Dave Thomas, who may well be a very pragmatic guy.

The main thing of interest to me in the post is something related to why I think that the current hype about DSLs is becoming a bit onanistic and the BDD frameworks are at best a distraction.

If I understand correctly the crux of the problem is as follows. If we are touting these DSLs at domain experts in the belief that the domain experts who will be comfortable with these DSLs are business users, then we have a problem.

In the context of Applescript Dave makes the following observation:

Given ...

"... for years, I've been trying to get into AppleScript. I keep trying, and I keep failing. Because the language is deceptive. They try to make it English-like. But it isn't English. It's a programming language. And it has rules and a syntax that are very unEnglish like. There's a major cognitive dissonance—I have to take ideas expressed in a natural language (the problem), then map them into an artificial language ..."

When ...

"When you're writing logic like this, with exception handling, command sequencing, and (in more advanced examples) conditionals and loops, then what you're doing is programming. The domain is the world of code."

Then ...

"... who are the domain experts? That's a trickier question to answer. In an ideal world, it would be the business users. But, the reality is that if the business users had the time, patience, an inclination to write things at this level, they wouldn't need programmers. Don't kid yourselves—writing these specs is programming, and the domain experts are programmers.

I guess this is the real problem I have with all of this. Surely a specification (or specification language), however captured has to have the characteristics of a ubiquitous language. A programming language does not need to have this characteristic.

I'm thankful to Keith for pointing out the Cobol Fallacy to me as I think this has some bearing on this sorry tale of trying to create a natural language like DSL.

begin"to say that i believe"'bollix')