Question

I have a module which exists to be included in two similar classes. Some of the methods to be included in the module for identical use by both classes return a new instance.

But how to I encode in the module that the constructor for the containing class should be called?

A simplified example:

module Point3D
  def initialize(x,y,z)
    @x = x
    @y = y
    @z = z
  end

  def * (scalar)
    <myclass>.new(@x * scalar, @y * scalar, @z * scalar)
  end
end

class Vertex
  include Point3D
end

class Vector
  include Point3D
end

So in the definition of * how would i call the constructor such that in the context of the Vertex class it returned a new Vertex and in the context of the Vector class it returned a new Vector without redeclaring all such methods in each class?

Answer 1

You can call ‘class’ method to get the class of obj.

For this case, it’s

def * (scalar)
  self.class.new(...)
end