I'm working on several distinct but related projects in different programming languages. Some of these projects need to parse filenames written by other projects, and expect a certain filename pattern.
This pattern is now hardcoded in several places and in several languages, making it a maintenance bomb. It is fairly easy to define this pattern exactly once in a given project, but what are the techniques for defining it once and for all for all projects and for all languages in use?
Creating a Domain Specific Language, then compile that into the code for each of the target languages that you are using would be the best solution (and most elegant).
Its not difficult to make a DSL - wither embed it in something (like inside Ruby since its the 'in' thing right now, or another language like LISP/Haskell...), or create a grammar from scratch (use Antlr?). It seems like the project is large, then this path is worth your while.