title: Variables within .htaccess redirects
body: <p>I want to make reference to a variable called "foo" (with value "bar")</p>
  
  <pre><code>SetEnv foo bar
  </code></pre>
  
  <p>within a RewriteRule</p>
  
  <pre><code> RewriteRule ^([^/]*)/([^/]*)/$ /{foo}.php?p=$1&amp;id=$2 [L]
  </code></pre>
  
  <p>so that it <em>literally</em> reads as:</p>
  
  <pre><code>RewriteRule ^([^/]*)/([^/]*)/$ /bar.php?p=$1&amp;id=$2 [L]
  </code></pre>
  
  <p>How is this possible?</p>