code: function(options) {
          var elementName, type, focused;
  
          for (elementName in this.view) {
              var el = this.view[elementName],
                  value = controlValue(el).trim();
  
              if (
                  value === '' && elementName === 'operator' && // not in operator menu
                  this.root.conditionals.ops[this.operator] && // but valid in operator hash
                  !getProperty.call(this, this.column, 'opMustBeInMenu') // and is doesn't have to be in menu to be valid
              ) {
                  value = this.operator; // use it as is then
              }
  
              if (value === '') {
                  if (!focused && options && options.focus) {
                      clickIn(el);
                      focused = true;
                  }
                  if (options && options.throw) {
                      throw new this.Error('Missing or invalid ' + elementName + ' in conditional expression. Complete the expression or remove it.', this);
                  }
              } else {
                  // Copy each controls's value as a new similarly named property of this object.
                  this[elementName] = value;
              }
          }
  
          this.op = this.root.conditionals.ops[this.operator];
  
          type = this.getType();
  
          this.converter = type && type !== 'string' && this.converters[type];
  
          this.calculator = this.getCalculator();
      }
docs: Called by the parent node's {@link FilterTree#invalid|invalid()} method, which catches the error thrown when invalid.
  
  Also performs the following compilation actions:
  * Copies all `this.view`' values from the DOM to similarly named properties of `this`.
  * Pre-sets `this.op` and `this.converter` for use in `test`'s tree walk.
  
  @param {boolean} [options.throw=false] - Throw an error if missing or invalid value.
  @param {boolean} [options.focus=false] - Move focus to offending control.
  @returns {undefined} This is the normal return when valid; otherwise throws error when invalid.
  @memberOf FilterLeaf#