We can construct a daffodil/eclipse-projects directory, and put all the eclipse stuff for all sub-projects in there.

Take daffodil-core for example.

We could tuck the daffodil-core-unittest project, which exists purely for the benefit of eclipse, into eclipse-projects/core-unittest.

Then, we could create side by side with that, eclipse-projects/core.

core and core-unittest would each contain just a .project and a .classpath. daffodil-core directory itself would no longer be an eclipse project. The core would use the same tricks to reach the src/main that the core-unittest uses to reach the test directories. It's done via an eclipse linked resource.

Since the .project and .classpath files are both rooted by way of the DAFFODIL_ROOT variable, this would allow them to be entirely outside the sbt file structure.

so we end up with eclipse-projects/core, core-unittest, lib, lib-unittest, runtime1, runtime1-nittest, etc. etc.

we can even put the daffodil 'root' eclipse project in eclipse-projects/daffodil (or maybe eclipse-projects/root), and it won't cause the trouble it causes when eclipse projects are nested.