The alternative and more charitable interpretation, of course, is that a single function like sin() is not what said GP meant when using the word "interface". But hey, don't let me interrupt your tilting at straw men, you're doing a great job.
Appreciate the charitable interpretation. Both “complexity“ and “abstraction” take many different forms in software, and exceptions to the rule-of-thumb abound so it’s easy to come up with counter examples. Regardless, thinking in terms of complexity ratios has been a useful perspective for me. :)
IMO, a function _can_ be an interface in the broadest sense of that term. You’re just giving a name to some set of code you’d like to reuse or hide.
