Mixins and variables

ruby-talk
1

Hi,
I'm new to Ruby, and trying to figure out how the inheritance/mixin works:
I can't figure out how to set an instance variable with a mixin method
from the object's initialize().

Example:

···

-----------------
module TestMod
  def x
    @x
  end
  def x=(arg)
    @x=arg
  end
end

class TestClass
  include TestMod
  def initialize
    x=('alpha')
    printf("x=%s\n", x)
  end
end

irb(main)..>tmp=TestClass.new
x=alpha # x is set inside constructor
=> #<TestClass:0x37d9520>
irb(main)..>tmp.x
=> nil # x is unset on the returned object
-----------------

Does anyone know why it doesn't work? What can I do instead?

--
Johannes Friestad
johannes.friestad@gmail.com

2

Hi,
I'm new to Ruby, and trying to figure out how the inheritance/mixin works:
I can't figure out how to set an instance variable with a mixin method
from the object's initialize().

I see you have your answer, so let me just make some general comments:

Example:
-----------------
module TestMod
  def x
    @x
  end
  def x=(arg)
    @x=arg
  end

You can replace the last six lines with:

attr_accessor :x

end

class TestClass
  include TestMod
  def initialize
    x=('alpha')

self.x = 'alpha' # as discussed, or just @x = 'alpha'

    printf("x=%s\n", x)

And we would usually write that as:

puts "x=#{x}"

  end
end

Hope that gives you an idea or two.

James Edward Gray II

···

On Dec 6, 2005, at 11:06 PM, Johannes Friestad wrote: