Given the design constraints: """ A generic library should be able to calculate the distance: for any point class or struct, not on just this mypoint type

Given the design constraints: """ A generic library should be able to calculate the distance: for any point class or struct, not on just this mypoint type in more than two dimensions for other coordinate systems, e.g. over the earth or on a sphere between a point and a line or between other geometry combinations in higher precision than double avoiding the square root: often we don't want to do that because it is a relatively expensive function, and for comparing distances it is not necessary """ I suspect a little bit of complexity is necessary. (And can you even build something like this in a more fashionable language?)