title: Calculated Fields in web2py sqlgrid
body: <p>Web2py has several methods for calculated fields, but the documentation states that lazy fields "are not visualized by default in tables" because they don't come with attributes like _.  In fact, they don't seem to be able to be available in SQLFORM.grid even if the field is requested.  I get the error </p>
  
  <pre><code>AttributeError: 'FieldLazy' object has no attribute 'readable'
  </code></pre>
  
  <p>When I include a lazy field in the field list.</p>
  
  <pre><code>db.mytable.myfield = Field.Lazy(lambda row: "calc")
  </code></pre>
  
  <ul>
  <li>Can I put a lazy field into a grid?</li>
  <li>What is the recommended way to display a grid that includes calculated fields.</li>
  </ul>