[fpc-pascal] interface inheritance implementation

David Emerson david at angelbase.com
Tue Oct 13 03:34:30 CEST 2015

On 10/12/2015 03:13 AM, Graeme Geldenhuys wrote:
> t_multiplier_and_adder = class (tbase, i_adder, i_multiplier)

Thanks for this recommendation-- the problem is that I have a list whose 
elements are each i_multiplier_and_adder, and I want to be able to take 
an element of that list and have the full capability. So separating 
i_multiplier from i_adder creates a different problem.

The other recommendation was essentially to make a proper delegate that 
is not an instance of the ancestor interface. But that doesn't work for 
me, because -- as I wrote initially -- I have one instance of the 
ancestor, and multiple instances of the child that need to work 
differently for their own stuff but all call on the one singular 
ancestor instance for its interface.

So far I have not figured out how to typecast an interface into its 
implementing class, which would be an alternate solution for my 
particular situation.

For the time being, I guess there's no shortcut - I just have to 
implement all of the i_adder methods in i_multiplier_and_adder, and have 
them call the same method in the "hook" which is unable to be a delegate.

Thanks for your responses, all!


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