Comment by skydhash

2 days ago

> I guess I don't understand the argument here because those just sound like two different flavours of the same custard to me; the difference is just the balance of work you're doing on each side of the interface, and that decision depends on use cases specific to the project.

It is two different flavours. One is about interconnecting things, and the other is what you interconnect. What TFA called modelling abstraction seems to be the primitive ideas that goes in building more complex systems (which it calls Modularity Abstraction). Something like a String is not a primitive, but rather a combination of the idea of Character and List are. Just like you can go from a disk (a pure array of bytes) to a file system (in the unix world, a tree with nodes of metadata). The primitive here are Array (existing) and Tree (target) and with them you build a modular system (The file systems) that transform ones into another.

So yes, both are abstractions, one is about identifying primitives, and the other is about combining them.

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skydhash

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danparsonson  1 day ago

That just sounds like a tower of abstraction to me; the 'primitives' are whatever you're building the current layer on top of. The filesystem becomes the primitive when you want to fopen something. Perhaps I'm over simplifying? I still don't see a division into two classes of abstraction.

  • skydhash  1 day ago

    > That just sounds like a tower of abstraction to me;[...] I still don't see a division into two classes of abstraction.

    It is a tower of abstraction as it's recursive. It's just that at every layer you will be dealing with two types, the primitive from the previous layer and the new system that you're building in this layer. Something like Character is a composition of symbols (bit) and encoding (ASCII, Unicode), in a specific form of Data.

    DDD is kinda a meta on that where the emphasis is to simultaneously build a glossary (primitives) while also trying to define subdomains to restrict their semantic. But that's an approach for software architecture, not general system modeling.