title: openerp domain filters how to compare 2 fields in object?
body: <p>In Odoo/OpenERP I want to make a filter to compare field1 and field2 of the same object like below.</p>
  
  <p>Plz let me know how to make this filter work,  adding filter on partners search form:</p>
  
  <pre><code>                &lt;field name="credit_limit"/&gt;
                  &lt;field name="credit"/&gt;
  
                 &lt;filter name="credit limit" domain="[('credit','&gt;',credit_limit)]"/&gt;
  </code></pre>
  
  <p>Applying this filter gives below error:</p>
  
  <pre><code>Uncaught Error: Failed to evaluate search criterions:
  {"code":400,"message":"Evaluation Error","data":{"type":"local_exception","debug":"Local evaluation failure\nNameError: name 'credit_limit' is not defined\n\n{\"domains\":[[],\"[('customer','=',1)]\",\"[('credit','=',credit_limit)]\"],\"contexts\":[{\"lang\":\"en_US\",\"tz\":\"Africa/Cairo\",\"uid\":1,\"search_default_customer\":1}],\"group_by_seq\":[]}"}}
  </code></pre>
  
  <p>I googled many times to find a solution without finding anyone .</p>
  
  <p>the simple form [('credit_limit','&lt;',credit)] always returns the error "can not convert string to float" where string is credit and float is credit_limit.</p>
  
  <p>is there any way to say [('credit_limit','&lt;',valueof(credit))] or [('field1','=',valueof(field2))] ??</p>
  
  <p>Regards,</p>