I get what you're saying, but Ruby already allows you to do this. If you like an API/design, then go ahead and reimplement it however you like. There are no cla

I get what you're saying, but Ruby already allows you to do this. If you like an API/design, then go ahead and reimplement it however you like. There are no class-level contracts anywhere in Ruby that would prevent this, and therefore interfaces provide no additional level of abstraction that Ruby doesn't already have.