title: escape dot in variable names in jinja template
body: <p>I have jinja template file with variable names like x.y.z (like java package names). Then I'm using Python envtpl to generate actual config file from jinja template file using envtpl.process_file. But it errors out saying 'x' is undefined. I know in jinja dot means something else so how do I escape it so that envtpl understands that 'x.y.z' is a variable name not just 'x'.</p>
  <p>template file for example:</p>
  <pre><code>foo = &quot;{{ x.y.z | default(&quot;abc&quot;) }}&quot;
  bar = &quot;{{ a.b.c | default(&quot;123&quot;) }}&quot;
  </code></pre>