Re: Updated design document: decoupling
Peter Soetens <[email protected]>
| Newsgroups | gmane.science.robotics.orocos.user |
|---|---|
| Organization | KU Leuven |
| Message-ID | <[email protected]> |
On Sunday 29 June 2003 12:25, Herman Bruyninckx wrote: > I've put a short document that explains my view on what "decoupling" > means for the design of complex software systems: > > <http://www.orocos.org/decoupling.html> > > As ever, feedback is very welcome! As I agree with most of the statements in this document, I have to add from personal experience the following drawbacks : Semantic decoupling (a drawing might be handy) : What I understand is that you want the programmer work with purely symbolic representations at one place and let him decide at another place what is underneath these representations. This sounds very much like generic programming, which involves template based design. There is no way to do this cleanly with polymorphic base classes, although some interfaces might handy. Maybe we might seek inspiration in boost.org based libraries. I only know very little people who are able to pull this. Small Interfaces : - means also many interfaces. The more interfaces exist, the more difficult it is to : 1) grasp their existence and working (they are often too abstract) 2) maintain them (need to edit many files if one changes) 3) design or refactor them (ditto) Library structure : More, fine grained libraries mean : 1) gigantic load on maintenance (double work, documentation, makefiles, scripts, installation etc) 2) gigantic load on development : Imagine that a 'root' library has changed an interface or so, then all depending libraries need to be recompiled and reinstalled _in the correct order_ ! Orocos@KUL has only 4 packages and we already experience time loss due to separate recompilation and installation when developping. As the proposal is correct in theory, I believe the practical constraints were not taken into account. Peter -- ------------------------------------------------------------------------ Peter Soetens http://www.orocos.org Katholieke Universiteit Leuven Division Production Engineering, tel. +32 16 322773 Machine Design and Automation fax. +32 16 322987 Celestijnenlaan 300B [email protected] B-3001 Leuven Belgium http://www.mech.kuleuven.ac.be/pma ------------------------------------------------------------------------