want_a_closure.rb

  def build_conditions
    conditions = []
    def condition(cond, &f)
      if block_given?
        conditions.concat yield(cond)
      else
        conditions.concat lambda {|c| {c => params{c}}}.call
      end
    end
    condition("address") do |addr|
      ["adddress like ?", addr]
    end
    conditions
  end