Currently, the Groovy compiler supports extension methods only if they are previously compiled and provided to the current compilation run on the classpath. I have several projects where using extension methods to make project-specific micro-DSLs would substantially improve readability/maintainability, but because the extension methods need to refer to business objects, I would have to slice up the project into a pile of micro-projects.
It would be very useful to be able to have a "bootstrap" mechanism to declare extension methods within the same project they're applied to, in the same way that annotations can be declared inside the same project. Either having an annotation @ProvidesExtensionMethods or providing a META-INF file (maybe being able to employ the usual mechanism for "forward extension declarations"?) would accomplish what I think I'm looking for.