Re: [Zope3-Users] Re: Newbie Question
On Feb 23, 2007, at 5:14 PM, Philipp von Weitershausen wrote: Edward Muller wrote: I've done Zope2 stuff in the past, including writing Zope2 Products. We are working on new hosting software and have decided to use Zope 3. So we're defining our interfaces and have started to define classes based on those interfaces and I have a question... The simple todo app (http://worldcookery.com/files/jeffshell-todo/ step1.html) shows the Todo class having three attributes (description, details, done). These are all defined in the interface using various zope.schema definitions. But ... The Boring product (http://products.nidelven-it.no/zope3_boring/) does the same thing in the interface with a title attribute. But when it gets to the class definition it uses: def __init__(self, title='Default boring title'): self.title = title The later is more familiar to me coming from Zope 2. Which is right? If they are both right, which is *more* right wrt Zope 3 ... and why? With respect to interfaces, it's always a good idea to have your objects, incl. newly created ones, comply to the interfaces they promise to implement. In particular, this means that they should have default values for the schema attributes. Frameworks like zope.formlib also happen to rely on that. My book also happens to show class-level attributes a lot. Lately I've come to prefer initializing attributes in the constructor (__init__) instead, though. It's really a matter of taste, in the end. If you like initializing them in the constructor, go with that... By initializing attributes in the constructor do you mean: A) class IA(): The Letter A letter = zope.schema.TextLine(title=The Letter A) class A(): implements(IA) def __init__(self,...): letter = A or B) class A() implements(IA) def __init__(self,...): self.letter = A -- http://worldcookery.com -- Professional Zope documentation and training Next Zope 3 training at Camp5: http://trizpug.org/boot-camp/camp5 ___ Zope3-users mailing list Zope3-users@zope.org http://mail.zope.org/mailman/listinfo/zope3-users -- Edward Muller Interlix, LLC Owner Zope, Plone Zimbra Hosting phone: +1.417.862.0573 fax: +1.770.818.5437 -- ___ Zope3-users mailing list Zope3-users@zope.org http://mail.zope.org/mailman/listinfo/zope3-users
Re: [Zope3-Users] Re: Newbie Question
On 24 Feb 2007, at 16:05 , Edward Muller wrote: By initializing attributes in the constructor do you mean: A) class IA(): The Letter A letter = zope.schema.TextLine(title=The Letter A) class A(): implements(IA) def __init__(self,...): letter = A This is pretty ineffective, it doesn't store 'letter' on self. or B) class A() implements(IA) def __init__(self,...): self.letter = A I mean that. Actually, I mean: class A: implements(IA) def __init__(self, a, b, c): self.a = a self.b = b self.c = c perhaps with default values for a,b,c if it makes sense for you. ___ Zope3-users mailing list Zope3-users@zope.org http://mail.zope.org/mailman/listinfo/zope3-users
Re: [Zope3-Users] Re: Newbie Question
Thanks. The book is on order with amazon. I just want to get as much done as possible while I'm at pycon and away from customers ... and motivated ... etc. On Feb 23, 2007, at 4:43 PM, Martin Aspeli wrote: Edward Muller wrote: I've done Zope2 stuff in the past, including writing Zope2 Products. We are working on new hosting software and have decided to use Zope 3. So we're defining our interfaces and have started to define classes based on those interfaces and I have a question... The simple todo app (http://worldcookery.com/files/jeffshell-todo/ step1.html) shows the Todo class having three attributes (description, details, done). These are all defined in the interface using various zope.schema definitions. But ... The Boring product (http://products.nidelven-it.no/zope3_boring/) does the same thing in the interface with a title attribute. But when it gets to the class definition it uses: def __init__(self, title='Default boring title'): self.title = title The later is more familiar to me coming from Zope 2. Which is right? If they are both right, which is *more* right wrt Zope 3 ... and why? They are both right, and it doesn't matter. The interface says when you have an instance of this object, you can expect there to be a 'title' attribute. How it got there is not that important. By the way, if you're starting with Zope 3, get Philipp von Weitershausen's book Web Component Development with Zope 3 (www.worldcookery.com). It'll make a lot of this stuff much more clear. Martin ___ Zope3-users mailing list Zope3-users@zope.org http://mail.zope.org/mailman/listinfo/zope3-users -- Edward Muller Interlix, LLC Owner Zope, Plone Zimbra Hosting phone: +1.417.862.0573 fax: +1.770.818.5437 -- ___ Zope3-users mailing list Zope3-users@zope.org http://mail.zope.org/mailman/listinfo/zope3-users
[Zope3-Users] Re: Newbie Question
Edward Muller wrote: I've done Zope2 stuff in the past, including writing Zope2 Products. We are working on new hosting software and have decided to use Zope 3. So we're defining our interfaces and have started to define classes based on those interfaces and I have a question... The simple todo app (http://worldcookery.com/files/jeffshell-todo/step1.html) shows the Todo class having three attributes (description, details, done). These are all defined in the interface using various zope.schema definitions. But ... The Boring product (http://products.nidelven-it.no/zope3_boring/) does the same thing in the interface with a title attribute. But when it gets to the class definition it uses: def __init__(self, title='Default boring title'): self.title = title The later is more familiar to me coming from Zope 2. Which is right? If they are both right, which is *more* right wrt Zope 3 ... and why? With respect to interfaces, it's always a good idea to have your objects, incl. newly created ones, comply to the interfaces they promise to implement. In particular, this means that they should have default values for the schema attributes. Frameworks like zope.formlib also happen to rely on that. My book also happens to show class-level attributes a lot. Lately I've come to prefer initializing attributes in the constructor (__init__) instead, though. It's really a matter of taste, in the end. If you like initializing them in the constructor, go with that... -- http://worldcookery.com -- Professional Zope documentation and training Next Zope 3 training at Camp5: http://trizpug.org/boot-camp/camp5 ___ Zope3-users mailing list Zope3-users@zope.org http://mail.zope.org/mailman/listinfo/zope3-users
