Tkinter callback arguments

Alf P. Steinbach alfps at
Thu Nov 5 10:04:15 CET 2009

* Gabriel Genellina:
> En Wed, 04 Nov 2009 18:08:49 -0300, Alf P. Steinbach <alfps at> 
> escribió:
>> * Terry Reedy:
>>> Alf P. Steinbach wrote:
>>>> However, the natural semantics is that various logical properties, 
>>>> such as left, top, right, bottom, width and height, can be varied 
>>>> independently.
>>>  But they *CANNOT* be varied independently. A rectangle with side 
>>> parallel to the axes has exactly 4 degress of freedom, not 6.
>> Yes <g>. That's the basic idea of the example I presented up-thread, 
>> that's discussed here. With R1's state variables width and heigh can 
>> be varied independently by direct modification, with R2 it's right and 
>> bottom.
>> The public interface must also make this choice, but it's an 
>> independent choice: the internal rectangle representation can have the 
>> opposite choice.
>> And conversely, that means that if the internal representation isn't 
>> used directly, then it can be changed without affecting the public 
>> interface.
> And that's exactly what everyone is saying - so we all agree then!

Well, it may be that we *violently* agree. :-)


- Alf

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