title: Why does '->'(12, b) give an error?
body: <p>In R operators can also be expressed as a function call, e.g.</p>
  
  <pre><code>'&lt;-'(b, 12)
  </code></pre>
  
  <p>for <code>b &lt;- 12</code>.<br>
  Why does the following give an error:</p>
  
  <pre><code>'-&gt;'(12, b)
  </code></pre>
  
  <p>? (The code <code>12 -&gt; b</code> works as expected.)</p>