title: In R, can I change histogram title without specify `main=`?
body: <p>Ok, suppose I create a very simple histogram with my function:</p>
  
  <pre><code>hist(my.fun(100))
  </code></pre>
  
  <p>The title of my histogram show <code>Histogram of my.fun(100)</code>. This is perfectly fine for me! I like the way R automatically recognize <code>my.fun(100)</code> and put it in the title and label.</p>
  
  <p>But then I do complex computation, says:</p>
  
  <pre><code>n &lt;- my.complex.algo.that.compute.size(args)
  hist(my.fun(n))
  </code></pre>
  
  <p>This time, the title show <code>Histogram of my.fun(n)</code>. Which gives no clue on how large is <code>n</code>. I know that <code>n</code> will be evaluate to some integer, suppose that for this run <code>n == 42</code>, I like to see the title of histogram show <code>Histogram of my.fun(42)</code> instead.</p>
  
  <p>Is this possible <em>without</em> specifying the title by myself (no <code>main=paste(...)</code>). I've try these and fail:</p>
  
  <pre><code>hist(my.fun(`n`))
  hist(my.fun(eval(n)))
  </code></pre>