this post was submitted on 03 Jul 2023
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You're not describing composition.
Go Files do not "hasa reader". You don't do file.reader.read(), you just do file.read(), that's inheritance as file has inherited the read() method.
You're confusing polymorphism for inheritance.
readis a method on an interface thatFileimplements - it is not inherited from a base class. You can use thatFiledirectly, or wherever aReaderinterface (or whatever the name is, idk I don't really do Go) is expected.Composition do not necessitate the creation of a new field like x.reader or x.writer, what are you on?
https://www.infoworld.com/article/3409071/java-challenger-7-debugging-java-inheritance.html#toc-2
composition is literally the "has a" relationship. That's how its always been taught.
Man, I honestly have no idea why they are downvoting you. Composition literally means taking common behavior and placing it in external objects behind interfaces using a has-a relationship.
No idea why they are denying this. Inheritance vs composition is the same as "is-a" vs "has-a". In composition re usability isn't done via inheritance but code encapsulation.
Saying that in Go objects can implement many interfaces is the Interface Segregation principle from SOLID. Basically having small interfaces instead of a big interface with methods that may not be implemented by all implementors.