[kragen]

Sounds like you haven't ever tried to implement it. But if the "case" you're thinking of is the "case" narnarpapadaddy was referring to, that takes us to their clause, "Any fewer [cases], the additional abstraction is unneeded complexity." This is obviously absurd when we're talking about the sin() function. Therefore, that can't possibly have been their intended meaning.

[tremon]

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.

[narnarpapadaddy]

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.