On Domain-Specific Language Usage

Many years ago (I will not reveal my age), I began working on my PhD thesis concerning the area of Domain-Specific Languages (DSLs). Research was booming at the time and many research articles stated in their introduction that DSLs are very useful and increase productivity, by reducing lines of code etc. All these claims seemed logical to me, but I always considered them something like urban legends. We all know that they are correct, but cannot easily prove it. Keeping that on the back of my mind, I searched for a way to bring the “legend” down to measurable facts that will provide solid motivation for the importance DSLs in every day programming. I decided to do a simple experiment that measures DSL usage in open source programs.

My attack vector was simple; I narrowed down my data set to Java programs and measured package usage of application libraries that implemented DSLs. I selected Java for two reasons; first, it was easier to find and mine open source projects semi-automatically with a little scripting (python) by using the maven repository and second, the Java Standard Development Kit includes many application libraries that enable DSL support. At first, a snapshot (January 2012) of the Maven repository was downloaded locally. The repository contained various projects and their versions, which usually indicate a major release. All versions were filtered out and only the most…