Foo.rb

class Foo
  attr_accessor :bar
  def initialize
    @bar = 'init'
  end
  def fun
    lambda { "got: #{@bar}" }
  end
  def fun2
    b = @bar
    lambda { "got: #{b}" }
  end
end
def try_me(fn)
  fn.call
end
foo = Foo.new
puts try_me(foo.fun)
puts try_me(foo.fun2)
fn = foo.fun

foo.bar = 'newbar'

puts fn.call
puts try_me(fn)
puts try_me(foo.fun)
puts try_me(foo.fun2)