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There's just not much about this that's unique to OOP. It's just defunctionalization, combined with "add another layer of indirection" to implement dynamic disp

There's just not much about this that's unique to OOP. It's just defunctionalization, combined with "add another layer of indirection" to implement dynamic dispatch and something like existential types. It can definitely be useful in some cases, but the way OOP proponents frame this does not seem very helpful. Always remember the YAGNI!

boomlinde 8y ago
It's true that there is not much about it that's unique to OOP, but that can be said of most high level programming concepts. They're just the cobbling-together of lower level abstractions. I just wanted to demonstrate why message passing via dynamic dispatch isn't so fundamentally different from static dispatch, conceptually, and to which extent it really is "making calls and sometimes they get picked up or not" compared to any other dispatch mechanism. Kay might disagree with this on the basis that late binding is important and that an object should not need to know what messages it will be passed at run-time; that the message is just that, a message rather than a contract. The only contract that exists is that an object should be able to receive a message, any message. But even with checked method calls like in Java I think the fundamental idea that you shouldn't have to consider what effect a method has on an object remains. What a language like Java adds is contracts like abstract classes or interfaces, essentially a way to tell the type checker what messages may be passed to an object. I agree that this approach can be useful in some cases and also think that you most likely not only AGNI, but that it will cause serious headaches and existential dread when applied to the wrong problem. So will Java. IMO OOP is suffering a bit of a backlash not because it's a particularly bad, but because like a Swiss army knife it looks deceptively applicable to a wider range of problems than it really is.
jimbokun 8y ago
"It's just defunctionalization, combined with "add another layer of indirection" to implement dynamic dispatch and something like existential types." But isn't this a pretty good working definition of "Object Oriented Programming"?

boomlinde 8y ago

It's true that there is not much about it that's unique to OOP, but that can be said of most high level programming concepts. They're just the cobbling-together of lower level abstractions. I just wanted to demonstrate why message passing via dynamic dispatch isn't so fundamentally different from static dispatch, conceptually, and to which extent it really is "making calls and sometimes they get picked up or not" compared to any other dispatch mechanism. Kay might disagree with this on the basis that late binding is important and that an object should not need to know what messages it will be passed at run-time; that the message is just that, a message rather than a contract. The only contract that exists is that an object should be able to receive a message, any message. But even with checked method calls like in Java I think the fundamental idea that you shouldn't have to consider what effect a method has on an object remains. What a language like Java adds is contracts like abstract classes or interfaces, essentially a way to tell the type checker what messages may be passed to an object. I agree that this approach can be useful in some cases and also think that you most likely not only AGNI, but that it will cause serious headaches and existential dread when applied to the wrong problem. So will Java. IMO OOP is suffering a bit of a backlash not because it's a particularly bad, but because like a Swiss army knife it looks deceptively applicable to a wider range of problems than it really is.

jimbokun 8y ago

"It's just defunctionalization, combined with "add another layer of indirection" to implement dynamic dispatch and something like existential types." But isn't this a pretty good working definition of "Object Oriented Programming"?