xml-dev - Re: XML Schemas: Best Practices

["Thomas B. Passin" <tpassin@home.com>]

Len Bullard said -

> Which in effect says that while I might create a
> universal definition of car, and even put it in a
> class of vehicle, on up to System.Object,
> the definition will be very thin and
> the vehicle, thinner.  Interface and implementation
> inheritance have to be different things or we
> are back to a tight coupling.  Now one has to decide if
> it is worth carrying around a lot of abstractions in
> the system, or if it is really ONE system at all.
>

In manufacturing, we used to talk about "form, fit, and function".  If a
part or assembly met these three, you could use it in place of the
original.  Other differences didn't matter.  It was almost like an
mantra for some people...
"Function" would correspond to the actual responses a component
provides - what it does.  Note that this is NOT implementation.  "Form"
referred to size, shape, maybe weight, and so on, so it would correspond
to interface. "Fit" had to to with tolerances and interconnections, so
that seems to be part of interface too.

Yes, interface and implementation are very different.  Good to remember.

Cheers,

Tom P