I think the argument is that: > It was a list of order totals. You can only say this knowing (basically): > map is a function which, for each item in a list,

I think the argument is that: > It was a list of order totals. You can only say this knowing (basically): > map is a function which, for each item in a list, in order, executes a function on that item and populates a new list with the returned value of that function. (I'm sure that description is technically wrong or misstated on some level.) And that goes back to the original post. map is jargon, meaning basically what I posted above. If you don't know the jargon, it looks a lot like obfuscating cleverness.