From: 7stud -- <bbxx789_05ss@...>
Date: 2008-02-25T10:03:47+09:00
Subject: Re: Suprising behaviour with "def property=" method

Farrel Lifson wrote:
> I had a bit of a surprise with the following
> 
> class Foo
>   def bar(value)
>     @bar = value.upcase
>   end
> end
> 
> f = Foo.new
> my_bar = (f.bar = "bar")
> 
> I initially thought that my_bar would == "BAR" but in fact it equals
> "bar". It seems no matter what the final value of the bar= method is
> the return value is always the parameters. First time I've run into
> this so I thought I would share and ask if anyone can think of anyway
> to get around this?
> 
> Farrel

I'm not sure why the return value of calling bar= is the method 
argument, but it makes sense to me that the return value is not the 
*private* instance variable's value.  If the return value were the 
private instance variable's value, that would break the encapsulation 
that a class is supposed to provide:

class Dog
  def secret_code=(seed)
    @secret_code = seed * 10 + 2
  end
end

d = Dog.new
return_val = (d.secret_code=(3) )
puts return_val    #should this reveal the secret code?
-- 
Posted via http://www.ruby-forum.com/.