Qustions about hierarchaly library conventions

Hi all, I have a qustion about a convention when writing a hierarchal library. Lets say I have a library A.B.C with modules A.B.C C1.hs C2.hs C3.hs Is there a convention (official or not) as to when there is a parent module (in the example above, C.hs) that imports and re-exports the various sub-modules? For example, in the standard libraries, there is a Foreign module that re-exports most of Foreign.*. But there isn't a System.Posix; you have to import the System.Posix.Signal and System.Posix.Types individually. Thanks. -- Matthew Donadio (m.p.donadio@ieee.org)