Re: [Pyobjc-dev] always replace colons with underscores... most of the time

[Bill B. <bb...@ma...>]

On Nov 11, 2007, at 1:23 PM, Chris McClimans wrote:
> class Person(NSObject):
>     personName = objc.ivar()
>     expectedRaise = objc.ivar.float()
>     def setExpectedRaise_(self, expectedRaise):
>         self.expectedRaise = expectedRaise
>     def setPersonName_(self, personName):
>         self.personName = personName
>
> It looks like it should work fine for KVC, however the trailing
> underscores on the setAttribute_ calls are not valid. If you replace
> the colons in the objective-c calls with underscores in python as I
> have seen else where, you will get an error when using KVC via an
> NSArrayController.
>
> An unexpected error occured: (AttributeError: 'Person' object has no
> attribute 'setExpectedRaise')
>
> This is resolved when removing the trailing underscore from the method
> call.
>
> Is this an exception to the replace colons in objective-c with
> underscores in python rule?

The above code looks slightly unexpected.  Namely, it doesn't  
implement the -expectedRaise and -personName instance methods.

Try implementing expectedRaise() and personName() methods (moving the  
iVars to _personName and _expectedRaise) most likely.

It is likely that NSArrayController is confused by the lack of the  
expected method pair.

Note that it is NSAC that is tripping over this, not KVC:

 >>> from Foundation import *
 >>> from objc import *
 >>> class Person(NSObject):
...     personName = objc.ivar()
...     expectedRaise = objc.ivar.float()
...     def setExpectedRaise_(self, expectedRaise):
...         self.expectedRaise = expectedRaise
...     def setPersonName_(self, personName):
...         self.personName = personName
...
 >>> x = Person.new()
 >>> x.valueForKey_("expectedRaise")
0.0
 >>> x.setValue_forKey_(10.0, "expectedRaise")
 >>> x.valueForKey_("expectedRaise")
10.0
 >>> x.expectedRaise
10.0
 >>> x.setExpectedRaise_
<selector setExpectedRaise: of <Person: 0x1ae7490>>

(stock Leopard)

b.bum