gistfile1.txt

thq-m-ismit01:~ ismith$ irb
1.9.3-p545 :001 > class Foo
1.9.3-p545 :002?>   attr_accessor :bar
1.9.3-p545 :003?>   def get_val(b = @bar) ; b; end
1.9.3-p545 :004?>   end
 => nil 
1.9.3-p545 :005 > f = Foo.new ; f.bar = 3
 => 3 
1.9.3-p545 :006 > f.get_val
 => 3 
1.9.3-p545 :007 > f.get_val(2)
 => 2 
1.9.3-p545 :008 > f.bar = 1
 => 1 
1.9.3-p545 :009 > f.get_val
 => 1 
1.9.3-p545 :010 >