Re: [Zope3-Users] __init__ method never called?

2006-09-19 Thread FB 
Hi,

On Mon, Sep 18, 2006 at 03:37:28PM +0100, John Smith wrote:
 Hi everyone!
 
 the class
 zope.app.publisher.browser.fileresource.FileResource
 inherits from BrowserView and Resource in that order.
 
 As far as I can work out, the __init__ method in
 Resource
 (zope.app.publisher.browser.resource.Resource) is
 never called.

(Please correct me if I'm wrong, I'm not a Python guru :-) )

Whenever you inherit from two classes, only the first class'
__init__ method is called implicitely on create of a new instance.

If you want both base classes' init method to be called, do something
like this:

class MyView(BrowserView,Second):
   def __init__(self,context,request):
  BrowserView.__init__(self,context,request)
  Second.__init__(self,context,request)

Regards,

Frank
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Re: [Zope3-Users] __init__ method never called?

2006-09-19 Thread FB 
Hi,

On Tue, Sep 19, 2006 at 04:53:45AM -0400, Stephan Richter wrote:
 On Tuesday 19 September 2006 03:47, FB wrote:
  (Please correct me if I'm wrong, I'm not a Python guru :-) )

[snip]

  class Join(First, Second):
 ... def __init__(self):
 ... print 'init 3-before'
 ... super(Join, self).__init__()
 ... print 'init 3-after'
 ...
  Join()
 init 3-before
 init 1-before
 init 2-before
 init 2-after
 init 1-after
 init 3-after
 __main__.Join object at 0xb7b5fb6c
 
 

Thank you for the clarification, Stephan. I know the meaning of 'super' a
lot better now.

Regards,

Frank
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Re: [Zope3-Users] __init__ method never called?

2006-09-19 Thread Stephan Richter 
On Tuesday 19 September 2006 03:47, FB wrote:
 (Please correct me if I'm wrong, I'm not a Python guru :-) )

 Whenever you inherit from two classes, only the first class'
 __init__ method is called implicitely on create of a new instance.

 class First(object):
...     def __init__(self):
...         print 'init 1-before'
...         super(First, self).__init__()
...         print 'init 1-after'
...
 class Second(object):
...     def __init__(self):
...         print 'init 2-before'
...         super(Second, self).__init__()
...         print 'init 2-after'
...
 class Join(First, Second):
...     def __init__(self):
...         print 'init 3-before'
...         super(Join, self).__init__()
...         print 'init 3-after'
...
 Join()
init 3-before
init 1-before
init 2-before
init 2-after
init 1-after
init 3-after
__main__.Join object at 0xb7b5fb6c


Regards,
Stephan
-- 
Stephan Richter
CBU Physics  Chemistry (B.S.) / Tufts Physics (Ph.D. student)
Web2k - Web Software Design, Development and Training
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Re: [Zope3-Users] __init__ method never called?

2006-09-19 Thread John Smith 
Hi,
both Resource and BrowserView have a common parent
class, viz Location, whose parent class is object.

   object
 |
 |
 Location
   /   \
  / \
 /   \
   BrowserView   Resource
 \/
  \  /
   \/
FileResource


As there are no calls to super() in any of the
definitions of BrowserView, Reource, FileResource or
Location, only the __init__ method of BrowserView
would appear to be called because attribute lookup
proceeds through the parent classes in the order they
are provided in the definition.

This can be practically tested by inserting a
NotImplementedError into to the definition of
Resource.__init__.

I'm pretty certain that that method is never called,
unless perhaps somewhere else in zope there is another
class that inherits from it first.

Cheers,

John.


--- Stephan Richter [EMAIL PROTECTED]
wrote:

 On Tuesday 19 September 2006 03:47, FB wrote:
  (Please correct me if I'm wrong, I'm not a Python
 guru :-) )
 
  Whenever you inherit from two classes, only the
 first class'
  __init__ method is called implicitely on create of
 a new instance.
 
  class First(object):
 ... def __init__(self):
 ... print 'init 1-before'
 ... super(First, self).__init__()
 ... print 'init 1-after'
 ...
  class Second(object):
 ... def __init__(self):
 ... print 'init 2-before'
 ... super(Second, self).__init__()
 ... print 'init 2-after'
 ...
  class Join(First, Second):
 ... def __init__(self):
 ... print 'init 3-before'
 ... super(Join, self).__init__()
 ... print 'init 3-after'
 ...
  Join()
 init 3-before
 init 1-before
 init 2-before
 init 2-after
 init 1-after
 init 3-after
 __main__.Join object at 0xb7b5fb6c
 
 
 Regards,
 Stephan
 -- 
 Stephan Richter
 CBU Physics  Chemistry (B.S.) / Tufts Physics
 (Ph.D. student)
 Web2k - Web Software Design, Development and
 Training
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[Zope3-Users] __init__ method never called?

2006-09-18 Thread John Smith 
Hi everyone!

the class
zope.app.publisher.browser.fileresource.FileResource
inherits from BrowserView and Resource in that order.

As far as I can work out, the __init__ method in
Resource
(zope.app.publisher.browser.resource.Resource) is
never called.

does anyone know if that Resource.__init__ method is
used by anything else?

Thanks,

John






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