I think that symmetry with structs is not that great of idea as initially appears. In one of previous discussions I've proposed an alternative approach:
I really believe that Rust should get named arguments eventually. And it's not about convenience or being more friendly to people coming from dynamic languages, but about helping to prevent bugs and thus making software more reliable (i.e. to be closer to Ada, not Python). And I did encounter bugs which could've been solved by named arguments, for example flat_projection uses lon/lat order instead of a more common lat/lon order (motivation being that lon/lat mirrors X/Y), which I've used automat…