I want my projects top level Rakefile to build things using rakefiles deeper in the tree; i.e. the top level rakefile says how to build the project (big picture) and the lower level ones build a specific module (local picture).

There is of course a shared set of configuration for the minute details of doing that whenever it can be shared between tasks: so it is mostly about keeping the descriptions of what needs building, as close to the sources being built. E.g. /Source/Module/code.foo and cie should be built using the instructions in /Source/Module/Rakefile; and /Rakefile understands the dependencies between modules.

I don't care if it uses multiple rake processes (ala recursive make), or just creates separate build environments. Either way it should be self-containable enough to be processed by a queue: so that non-dependent modules could be built simultaneously.

The problem is, how the heck do you actually do something like that with Rake!? I haven't been able to find anything meaningful on the Internet, nor in the documentation. I tried creating a new Rake::Application object and setting it up, but whatever methods I try invoking, only exceptions or "Don't know how to build task ':default'" errors get thrown. (Yes, all rakefiles have a :default). Obviously one could just execute 'rake' in a sub directory for a :modulename task, but that would ditch the options given to the top level; e.g. think of $(MAKE) and $(MAKEFLAGS).

Anyone have a clue on how to properly do something like a recursive rake?