Re: [Modeling-users] Handling custom types for attributes

[Mario R. <ma...@ru...>]

>> I would like to use custom FixedPoint values for an attribute of an  
>> object.
>> So, I do as the example in Chapter 9 of the userguide suggests... so 
>> I  define
>> the "private" methods obj._setX(val) and obj._getX(). However, when 
>> the
>> client code calls the corresponding public setX and getX methods, the
>> private ones are never called! Any ideas what I may be missing out on?
>> I am using 0.9-pre-16 of modeling plus bug862182.patch
>> (no other patches I think).
>
> Well, I think there should be something obscure in the doc. if it made
> you think that public methods call the corresponding private ones. It 
> is
> definitely not the case (at least by default, nothing prevents you from
> doing this).
>
>   Private accessors (as searched by KeyValueCoding.storedValueForKey)
>   are the only one used by the framework. That's why they can be used,
>   in particular, to define transformation from sql types to custom
>   types.
>
> Without more info. I cannot really tell why this bothers you so much :)

Hmmn, I have mis-assumed ;((

It bothers me because it does not do what I expect!
If I add the following "balance" methods to a MyCustomObject class:

   def _setBalance(self, value):
     if value is None:
       self._balance=None
     else:
       self._balance  = FixedPoint(value, 6)

   def _getBalance(self):
     if not self._balance:
       return None
     else:
       return str(self._balance)

Then, in an interactive session:

 >>> a = MyCustomObject()
 >>> a.getBalance()
''
 >>> a.setBalance(FixedPoint('123.456'))
 >>> a.getBalance()
FixedPoint('123.46', 2)
 >>>

Thus, on first getBalance() I should get None.
And on second getBalance() I should get a FixedPoint of pecision 6 not 
2.

I am missing something! It is late weekend, and I stop!

Cheers, mario