At 12:39 PM 9/29/2006, you wrote:
> On the other hand, I'm not sure pipelining in itself is any more (or
> less) "natural" than template matching;

Yes, but the point about maintainability isn't that the design is
necessarily easier to establish in the first place, it's that it's open to
change and resistant to structural decay once in place. In particular, new
functionality can often be introduced by adding a pipeline component, which
means there is minimal need to understand the internal logic of existing
components, and minimal risk of destabilizing them.

This makes sense; maybe I should be more careful to distinguish 
maintainability in this sense from "learnability", which has 
long-term maintenance implications of its own, but not perhaps with 
regard to the engineering as such. Both are virtues and in the ideal 
case, both are possible. Yet there are plenty of times when the 
sophisticated design most conducive to maintenance in the senses you 
describe might also be somewhat obscure or hard to understand, at 
least to the beginner. (Then they get that "aha" and what was 
baffling becomes beautiful.)



Of course, not every design has to be idiot-proofed, at least if one 
expects to be doing the maintenance oneself. Or maybe I should 
rethink that too....



Cheers,
Wendell