It does enable proxy shenanigans though, which is something to be mindful of:
I can be reasonably certain of what a reasonably complicated piece of logic is doing/capable of doing.
Comprehending a function using an object implementing a protocol, on the other hand, will end up requiring me to cross reference logic across 4 or more files before I can feel confident knowing what to expect: the protocol definition and/or the basic implementation, the calling context, the factory context that was responsible for creating the object, and the actual definition of the current object. All of which may be trivial, but you need to actually look at them all.
It's the difference between a breaker box and a house of light switches: the switches are all trivial (you hope), but you still hit the breaker when you need to be sure that you are going to be surprised.
Yeah. I'm kinda thinking about writing a blog post about that project, because I kinda like how it turns out.
Imo, the method I described to me is mostly reasonable to implement closed and fairly complete domain objects. In this case, understanding the protocol is more akin to understanding the concept from the problem domain, and the implementing classes are different cases or states the thing can be in. In your image, I'd compare the main thing I use this for as fuses. Simple, encapsulated and fulfilling a purpose - just implemented in different ways depending on the context.
On the other hand, if you're dealing with implementing a flow chart, I've grown to very much like a decently structured imperative function - supported by these smaller objects.
I can be reasonably certain of what a reasonably complicated piece of logic is doing/capable of doing.
Comprehending a function using an object implementing a protocol, on the other hand, will end up requiring me to cross reference logic across 4 or more files before I can feel confident knowing what to expect: the protocol definition and/or the basic implementation, the calling context, the factory context that was responsible for creating the object, and the actual definition of the current object. All of which may be trivial, but you need to actually look at them all.
It's the difference between a breaker box and a house of light switches: the switches are all trivial (you hope), but you still hit the breaker when you need to be sure that you are going to be surprised.