[Gambas-user] Direct assignment to arrays of inherited classes does not work

[Fabien Bodard]

for me if B inherit A so it can contain a A class ... it have the same
base struct...


For example in gb.report a reportcontrol can contain a ref to a
reportLabel witch inherit  reportcontrol... why it is not the same for
arrays ?

Fabien



2014-09-22 18:09 GMT+02:00 Fabien Bodard <gambas.fr at ...626...>:
> strange...
>
> has we can say Control = TextBox ... no ?
>
>
> 2014-09-22 11:03 GMT+02:00 Julio Sanchez <jusabejusabe at ...626...>:
>> Thanks Tobi, I'll try :)
>>
>> Regards,
>>
>> Julio
>>
>> 2014-09-22 10:46 GMT+02:00 Tobias Boege <taboege at ...626...>:
>>
>>> On Mon, 22 Sep 2014, Julio Sanchez wrote:
>>> > Direct assignment to arrays of inherited classes does not work
>>> >
>>> > We have a class that inherits from the integer class [], we call
>>> > SuperInteger, this is your code:
>>> > Inherits Integer []
>>> >
>>> > Public function  higher() as integer
>>> > dim itemt as integer
>>> > dim ihigher as integer
>>> >
>>> > for each element in me
>>> > ihigher = max (ihigher, item)
>>> > next
>>> >
>>> > return ihigher
>>> >
>>> > end
>>> >
>>> >
>>> > When I make an instance of the new :
>>> >
>>> > dim test as new SuperInteger
>>> >
>>> >
>>> > It does not work this assignment:
>>> > test = [86, 16, 212, 1, 43, 18]
>>> >
>>> > gambas3 says it's not the same type.
>>> > Should I working? Right?
>>> >
>>>
>>> No, because it is not the same type :-)
>>>
>>> Even if B inherits A, it can be very difficult to make sense of an
>>> assignment myB = myA because myB could reference _lots_ of other
>>> information (which is not in the class A). What should happen to this
>>> information in the assignment? You simply can't convert myA to the B
>>> class.
>>>
>>> The clean solution would be to define a static B.FromA() method which
>>> takes an A object and returns a new B object which contains that A
>>> object and initialises all other information appropriately.
>>>
>>> So, you would implement
>>>
>>>   Static Public Function FromArray(aArray As Integer[]) As SuperInteger
>>>
>>> or something along these lines in SuperInteger. For a more concise
>>> syntax, you may also use the _call() special method. Then you can do
>>>
>>>   myB = SuperInteger([1, 2, 3, 4])
>>>
>>> Regards,
>>> Tobi
>>>
>>> --
>>> "There's an old saying: Don't change anything... ever!" -- Mr. Monk
>>>
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>
>
>
> --
> Fabien Bodard



-- 
Fabien Bodard