Currently the hierarchical library proposal http://www.haskell.org/~simonmar/libraries/libraries.html does not say much about the semantics of the hierarchical module names. It really should.

I'm open to suggestions - in fact I thought the semantics were fairly clear, but perhaps not? Or do you mean that the document should say more about file names and searching policies? (that would be difficult without getting compiler-specific). Cheers, Simon