title: Check if no arguments passed
body: <p>Here's some code:</p>
  
  <pre><code>$ cat 1.rb
  #!/usr/bin/env ruby
  def f p1 = nil
      unless p1   # TODO
          puts 'no parameters passed'
      end
  end
  f
  f nil
  $ ./1.rb
  no parameters passed
  no parameters passed
  </code></pre>
  
  <p>The question is, is there a way to distinguish between no arguments and one <code>nil</code> argument passed?</p>
  
  <p><strong>UPD</strong></p>
  
  <p>I decided to add a use case in <code>javascript</code> to make things hopefully clearer:</p>
  
  <pre><code>someProp: function(value) {
      if (arguments.length) {
          this._someProp = value;
      }
      return this._someProp;
  }
  </code></pre>