From: 7stud -- <lists@...>
Date: 2012-11-28T04:20:16+09:00
Subject: Re: Novice: Understanding instance 'variables' and methods

First, I suggest that you learn more than one variable name.  Naming 
everything in your code test/Test/:test is just going to confuse you.

> I then added the 'attr_accessor :test' which presumably added a test=
> method, leaving the original 'test' method.

Writing attr_accessor :name inside a class is equivalent to writing:

def name    #getter
  @name
end

def name=(val)  #setter
  @name = val
end


And you call the 'name=' method like this:

d.name = 10

ruby ignores the space between 'd.name' and the '=' sign.


Once again, if you redefine a method it will overwrite an existing 
method:

class Dog
  attr_accessor :name
end

d = Dog.new
d.name = 'Sam'
puts d.name

--output:--
Sam


But see what happens here:

class Dog
  attr_accessor :name

  def name
    'hello'
  end
end


d = Dog.new
d.name = 'Sam'
puts d.name


--output:--
hello


The line attr_accessor :name tells ruby to create the methods:


def name    #getter
   @name
end

def name=(val)  #setter
  @name = val
end

...which ruby does.  Next ruby sees the definition:

  def name
    'hello'
  end


in the Dog class, and that name method overwrites the name method that 
ruby created.

-- 
Posted via http://www.ruby-forum.com/.