title: How to declare optional arguments in proc
body: <p>Could you help me how to use arguments with optionals I used this function but it does not work </p>
  
  <pre><code>proc {my_proc} {n1 n2 -args{{u2 "5"} {u1 "5"}} } {
  
  puts "n1:'$n1', n2:'$n2', u1:'$u1', u2:'$u2'"
  }
  
  -&gt;my_proc 1 -args 5 7
  n1:'1', n2:'$n2', u1:'7', u2:'5'
  </code></pre>
  
  <p>I would like to call function like </p>
  
  <ol>
  <li><code>my_proc 1 -args {u2 5} {u1 7}</code></li>
  <li><code>my_proc 1  {u2 5} {u1 7}  (required + optional arguments)</code></li>
  <li><code>my_proc 1 (only required arguments)</code></li>
  </ol>