Methods as in callbacks? So, code? Do you then store a closure or such? Or a pointer to one (i.e. the function/name)? And how or what data would modify behavio

Methods as in callbacks? So, code? Do you then store a closure or such? Or a pointer to one (i.e. the function/name)? And how or what data would modify behaviour? As said: I'm unfamiliar with these concepts as I actively try to avoid them :)