Re: [Zope-dev] ZPatterns Specialist Question
At 11:54 AM 7/3/00 +0100, Chris Withers wrote: >Just a quickie: > >If, as the the ZPatterns Wiki states, 'Specialists are not classes', >then why is there a 'Specialist' python class in the ZPatterns >distribution? > Specialists are instances of the class "Specialist". They are not themselves classes. The reason for emphasizing that point is that it is a common misconception of people beginning to use the ZPatterns design approach - they conflate or confuse specialists with the class of the things which they intend to use the specialist to gain access to. In other words, they assume that a specialist called "Customers" would always manipulate "Customer" instances, when in fact it might manipulate "SkyDiver" instances. Most of the point of having a specialist is to have a binding point which allows you to decouple your intended use of a thing, from the specific implementation of it. If one misses this point, one will be blind to a wide variety of ZPatterns' useful applications, and at the same time likely to ask why both Racks and Specialists are needed. They are both needed because the Specialist deals with a particular problem-domain aspect of a thing, and the Rack deals with implementation aspects. ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] ZPatterns Specialist Question
Steve Alexander wrote: > I think you're getting your levels of abstraction confused with your > meta-levels of abstraction :-) Confused? when talking about ZPatterns? n e v e r ;-) Chris ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] ZPatterns Specialist Question
Chris Withers wrote: > > Just a quickie: > > If, as the the ZPatterns Wiki states, 'Specialists are not classes', > then why is there a 'Specialist' python class in the ZPatterns > distribution? ZClasses are coded (implemented) using Python classes, and each instance of a ZClass represents a particular application-level class in Zope: DTML Methods are coded (implemented) using Python classes, and each instance of a DTML Method represents a particular application-level method in Zope. Specialists are coded (implemented) using Python classes, and each instance of a Specialist represents a particular ZPatterns Specialist object in Zope. I think you're getting your levels of abstraction confused with your meta-levels of abstraction :-) -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
