Looking Out To Sea

Nick’s just posted a succinct analogy for the interesting topic of evaluation strategies. However, it’s an analogy suitable for people who program in the first place because it doesn’t actually explain what call means.

Luckily it’s fairly simple. Though you have to pretend you remember high school mathematics. Can you pretend? Let’s assume so.

A function f is applied to an argument x, like this: f(x). In programming terms this is “calling f”. Calling means applying a function to an argument. We wrap the arguments in brackets for easy reading.

Nick’s post talks about how, specifically, we refer to x when we call f on x. Do we pass it the whole thing, or just tell f where to find it? These are considerations particular to computer programming — mathematics has no need to consider how much data is hidden behind a variable like x.