[sandal]

I've already written an entire book on this and given it away for free. I suggest you read it and write a review. Be specific, and show good counterexamples. I'll be happy to link you when you do.

Until then, stop acting like you're some sort of authority (NOTE: This is not to claim I am -- because I'm not and no one is.) I just think it'd make sense to put your ideas into a bit of context so people can see that you're not just being critical for the sake of being critical.

[richcollins]

    #from your book
    
    def distance(*points)
      case(points.length)
      when 2
        x1,y1,x2,y2 = points.flatten
      when 4
        x1,y1,x2,y2 = points
      else
        raise ArgumentError, "Points may be specified as [x1,y1], [x2,y2] or x1,y1,x2,y2"
      end
      Math.hypot(x2 - x1, y2 - y1)
    end

    puts distance(1, 2, 5, 6)
    puts distance([1, 2], [5, 6])

    # why would you choose to make a complicated interface that requires a complicated implementation?

    # simple, clear interfaces that allow for simple implementations
    # are almost always preferrable to complicated ones that save a
    # keystrokes through syntax

    class Point
      attr_accessor :x
      attr_accessor :y
  
      def initialize
        self.x = 0
        self.y = 0
      end
  
      def self.with(x, y)
        new.set(x, y)
      end
  
      def set(x, y)
        self.x = x
        self.y = y
        self
      end
  
      def distance_to(a_point)
        Math.hypot(a_point.x - x, a_point.y - y)
      end
    end

    puts Point.with(1, 2).distance_to(Point.with(5, 6))

[sandal]

So you mean that you prefer this:

Point.with(1, 2).distance_to(Point.with(5, 6))

Over this?

distance [1,2], [5,6]

I guess it depends on how many interesting things you wanted to do with points. As things get more complicated, maybe something like this is worthwhile, but I don't feel that making everything an explicit object is categorically better.

But the section you're quoting is among the most contrived examples that RBP gives, it's mainly just part of a list of the different sorts of argument processing Ruby offers and the trade-offs betweeen them.

Maybe you skimmed and missed that, or maybe you read through and chose to ignore that detail.

[stevedekorte]

The problems I have with "distance [1,2], [5,6]" are:

0. It breaks the fundamental OO convention and doesn't encapsulate logic and data.

1. It's not clear what it means unless you look up the docs.

2. It's implementation is complex, making it more difficult to understand and maintain

3. It fails to separate concerns, making it less extensible/modifiable. e.g. What if you wanted to override the setting behavior? You couldn't do it in one place.