Ruby: How should I access instance variables inside a class?

In ruby you can internally access variables directly via @var_name or via private getters attr_reader :var_name.

Which solution is more (semantically?) correct? Any advantages/disadvantages of using either solution 1 or solution 2?

Solution 1:

class Point
 def initialize(x, y)
   @x = x
   @y = y
 end

 def distance
   Math.sqrt(@x ** 2 + @y ** 2)
 end
end

Solution 2:

class Point
 def initialize(x, y)
   @x = x
   @y = y
 end

 def distance
   Math.sqrt(x ** 2 + y ** 2)
 end
 private attr_reader :x, :y
end