Challenge 2: define_method in a Loop — Solution

class Coordinate
  [:x, :y, :z].each do |axis|
    define_method(axis) do
      @values[axis]
    end
  end

  def initialize(x:, y:, z:)
    @values = { x: x, y: y, z: z }
  end
end

point = Coordinate.new(x: 1, y: 2, z: 3)
puts point.x
puts point.y
puts point.z

=begin
Output:
1
2
3

Notes:
- The each loop over [:x, :y, :z] runs at class-definition time (not per
  instance), calling define_method three times — once per symbol — each
  time generating a real instance method with that name.
- Every generated method has an identical body (return @values[axis]) but
  a different axis baked in via the block's closure over the loop
  variable — this is exactly why define_method takes a block instead of a
  method name plus separate body syntax.
- point.x, point.y, and point.z all work as ordinary method calls
  afterward — there's no way to tell from the caller's side that they were
  generated in a loop rather than written by hand with def.
=end