In the April 2009 issue of Communications of the ACM, Mike Shapiro of Sun (or should we say Oracle now?) has an interesting technical article about what he calls “purpose-built languages“. The article was earlier published in ACM Queue. Essentially, it is about domain-specific languages. He describes how many of the most useful little languages in use for the developmentof large systems have grown up without formal design, a grammar, or even a name.