Les Tyrrell said: 
> 
> One of the reasons I would not favor a TreeNode abastract class
> is that the thing I want to reuse is the pattern, and possibly
> multiple times within the same class.
> 
....
> That's why I do not bother with a commonly used TreeNode, but instead
> manually do the work that a parameterized mixin could do for me.  I
> do the rubberstamping because I currently do not have a facility within
> the system to accomplish the same goal.  Such a facility would have to
> manage more than simply stamping out code- I would want it to do
> things in a manner such that good software engineering and reuse
> practices become a natural part of working with the environment.
> 
> As far as running inheritance ( delegation, actually ) through
> patterns... that would be an interesting project for someone.
> The motivation is based on the observation that many patterns
> are used again and again, that there are variations in implementation
> of these patterns, and that quite often I am able to parameterize
> them and stamp them out on a grand scale.  At that point I am not
> writing individual methods nor specifying individual instance variables,
> I am saying "put this pattern into that class".  That is a different
> mode of programming, and it will require a different set of tools
> to facilitate it.  One aspect of that might be that it would be
....
> 
> BTW, I am sure that this is a somewhat different connotation for the
> word "pattern" than that used by the Patterns people... the problem 
> is that "pattern" is such an appropriate name for what I have in mind,
> but unfortunately it was appropriated decades ago and I don't have
> a decent replacement term to use instead.  So keep that in mind...
> I don't intend to redefine the term, I just haven't found a better name
> for what I'm after.
> 

I agree, this is a different use of "Pattern".  I think what you're
describing is what Gregory Kiczales calles "Aspect Oriented Programming".
see http://www.parc.xerox.com/spl/projects/aop/

-- 
Joe Davison 	jwdavison at lucent.com

	Sure it doesn't work as well as it used to, 
		but think of all the money we're saving.