From: Robert Feldt <feldt@...>
Date: 2001-05-07T23:20:00+09:00
Subject: [ruby-talk:14768] SimpleDelegator assymetry

Hi folks,

Can someone explain the "assymetry" in the behavior of the code below?

/Robert

require 'delegate'
class STB1; def b; 1; end; end
class STB2; def b; 2; end; end
class ANB < SimpleDelegator
  def initialize(o)
    super(o)
  end
  def change(o)
    __setobj__(o)
  end
end

def test(first, second)
  a1 = ANB.new(first)
  begin
    puts a1.b
  rescue NameError
    puts "1: Caught error"
  end
  a1.change(second)
  begin
    puts a1.b
  rescue NameError
    puts "2: Caught error"
  end
end

test(STB1.new, STB2.new) # Both ok.
test(STB1.new, nil)      # Ok, error on 2nd call since nil has no b method
test(nil, STB2.new)      # but why error on 2nd call here? 
                         # Or is it just my PoLS feeling that is wrong?
                         # Ps. PoLS = Principle of Least Surprise