docs: function parsedFrom() {
    var qtext = null;
    var bindings = null;
    var constraints = null;
    var term = null;
  
    switch(arguments.length) {
    case 0:
      throw new Error('no query text');
    case 1:
      qtext = arguments[0];
      break;
    case 2:
      qtext = arguments[0];
      bindings = arguments[1];
      constraints = bindings.constraint;
      term = bindings.term;
      break;
    default:
      throw new Error('parse from specifies only query text and bindings: '+mlutil.identify(arguments, true));
    }
  
    return new ParsedDef(new ParsedQueryDef(qtext, constraints, term));
  }