4 ms·

> Data modelling in OOP is an exercise in coming up with Platonic ideals, resulting in a hierarchical (tree-like) ontology as you try to choose of the atributes

> Data modelling in OOP is an exercise in coming up with Platonic ideals, resulting in a hierarchical (tree-like) ontology as you try to choose of the atributes as the categorisation dimension, and leaving everything else as properties. Only if that is how you choose to model the problem domain. > This is different than just asserting facts with data, which can lie in multiple dimensions. The "Is ..." examples you detail can just as easily be modeled "in OOP" as: class Animal { private knownFacts = ... def is (fact) ... } Without the need for "a hierarchical (tree-like) ontology", since obviously this would be a poor choice in this situation.

hcarvalhoalves 5y ago
Not the same thing, as the facts are now a property of Animal. My second example doesn't even mention Animal. You still have the problem of "putting things into a category" vs. just asserting facts.
- meheleventyone 5y ago
  There is an implicit subject you are asserting facts about though. You clearly are talking about a fluffy, white Cat in your example. It’s essentially structural rather than nominal typing. The “fluffy, white Cat” is defined by its traits. We could define a type Cat which has a subset of those traits and then be able to use our “fluffy, white Cat” anywhere we can use a Cat. We only name them to avoid having to name all the traits all the time. Doesn’t make it any less object based. Structural typing is really cool though. An object built from a named, saved recipe will work just as well as something cobbled together on the fly and at runtime you won’t even know which is which. It’s the basis of a lot of general purpose game engines composition based game object interface. I’ve also found it extremely fun to use with TypeScript.
  - hcarvalhoalves 5y ago
    > There is an implicit subject you are asserting facts about though. You clearly are talking about a fluffy, white Cat in your example. No, I'm not, because I didn't assert this fact (it's a Cat). See how hard it is to break free from this mindset of objects.
    - meheleventyone 5y ago
      Right as I said it’s structural typing. It’s implicit that the traits are grouped together to describe something. And individual traits could be grouped together with completely different ones to describe something else. That you choose not to name it doesn’t change that the trait collection applies to fluffy, white Cats whether you like that or not. I can even choose to call it one thing and you can choose to call it something else and the types will remain interchangeable. You can even leave your type anonymous and it will still be interchangeable.

hcarvalhoalves 5y ago

Not the same thing, as the facts are now a property of Animal. My second example doesn't even mention Animal. You still have the problem of "putting things into a category" vs. just asserting facts.

meheleventyone 5y ago
There is an implicit subject you are asserting facts about though. You clearly are talking about a fluffy, white Cat in your example. It’s essentially structural rather than nominal typing. The “fluffy, white Cat” is defined by its traits. We could define a type Cat which has a subset of those traits and then be able to use our “fluffy, white Cat” anywhere we can use a Cat. We only name them to avoid having to name all the traits all the time. Doesn’t make it any less object based. Structural typing is really cool though. An object built from a named, saved recipe will work just as well as something cobbled together on the fly and at runtime you won’t even know which is which. It’s the basis of a lot of general purpose game engines composition based game object interface. I’ve also found it extremely fun to use with TypeScript.
- hcarvalhoalves 5y ago
  > There is an implicit subject you are asserting facts about though. You clearly are talking about a fluffy, white Cat in your example. No, I'm not, because I didn't assert this fact (it's a Cat). See how hard it is to break free from this mindset of objects.
  - meheleventyone 5y ago
    Right as I said it’s structural typing. It’s implicit that the traits are grouped together to describe something. And individual traits could be grouped together with completely different ones to describe something else. That you choose not to name it doesn’t change that the trait collection applies to fluffy, white Cats whether you like that or not. I can even choose to call it one thing and you can choose to call it something else and the types will remain interchangeable. You can even leave your type anonymous and it will still be interchangeable.