title: error when calling batch file with no arguments
body: <p>I have a very simple batch script:</p>
  
  <pre><code>@echo off
  
  if %1 == a goto AA
  if %1 == b goto BB
  goto end
  
  :AA
  echo a
  goto end
  
  :BB
  echo b
  goto end
  
  :END
  echo on
  </code></pre>
  
  <p>If I call it with an argument <code>test.bat a</code>, I get what I expected, but if I call it without any arguments <code>test.bat</code>, I get <code>goto was unexpected at this time.</code> and the offending line is <code>if %1 == a goto AA</code>.</p>
  
  <p>Why?</p>