text: /**
   * @license
   * Visual Blocks Editor
   *
   * Copyright 2012 Google Inc.
   * https://developers.google.com/blockly/
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  /**
   * @fileoverview Checkbox field.  Checked or not checked.
   * @author fraser@google.com (Neil Fraser)
   */
  'use strict';
  
  goog.provide('Blockly.FieldCheckbox');
  
  goog.require('Blockly.Field');
  
  
  /**
   * Class for a checkbox field.
   * @param {string} state The initial state of the field ('TRUE' or 'FALSE').
   * @param {Function=} opt_validator A function that is executed when a new
   *     option is selected.  Its sole argument is the new checkbox state.  If
   *     it returns a value, this becomes the new checkbox state, unless the
   *     value is null, in which case the change is aborted.
   * @extends {Blockly.Field}
   * @constructor
   */
  Blockly.FieldCheckbox = function(state, opt_validator) {
    Blockly.FieldCheckbox.superClass_.constructor.call(this, '', opt_validator);
    // Set the initial state.
    this.setValue(state);
  };
  goog.inherits(Blockly.FieldCheckbox, Blockly.Field);
  
  /**
   * Character for the checkmark.
   */
  Blockly.FieldCheckbox.CHECK_CHAR = '\u2713';
  
  /**
   * Mouse cursor style when over the hotspot that initiates editability.
   */
  Blockly.FieldCheckbox.prototype.CURSOR = 'default';
  
  /**
   * Install this checkbox on a block.
   */
  Blockly.FieldCheckbox.prototype.init = function() {
    if (this.fieldGroup_) {
      // Checkbox has already been initialized once.
      return;
    }
    Blockly.FieldCheckbox.superClass_.init.call(this);
    // The checkbox doesn't use the inherited text element.
    // Instead it uses a custom checkmark element that is either visible or not.
    this.checkElement_ = Blockly.utils.createSvgElement('text',
        {'class': 'blocklyText blocklyCheckbox', 'x': -3, 'y': 14},
        this.fieldGroup_);
    var textNode = document.createTextNode(Blockly.FieldCheckbox.CHECK_CHAR);
    this.checkElement_.appendChild(textNode);
    this.checkElement_.style.display = this.state_ ? 'block' : 'none';
  };
  
  /**
   * Return 'TRUE' if the checkbox is checked, 'FALSE' otherwise.
   * @return {string} Current state.
   */
  Blockly.FieldCheckbox.prototype.getValue = function() {
    return String(this.state_).toUpperCase();
  };
  
  /**
   * Set the checkbox to be checked if newBool is 'TRUE' or true,
   * unchecks otherwise.
   * @param {string|boolean} newBool New state.
   */
  Blockly.FieldCheckbox.prototype.setValue = function(newBool) {
    var newState = (typeof newBool == 'string') ?
        (newBool.toUpperCase() == 'TRUE') : !!newBool;
    if (this.state_ !== newState) {
      if (this.sourceBlock_ && Blockly.Events.isEnabled()) {
        Blockly.Events.fire(new Blockly.Events.BlockChange(
            this.sourceBlock_, 'field', this.name, this.state_, newState));
      }
      this.state_ = newState;
      if (this.checkElement_) {
        this.checkElement_.style.display = newState ? 'block' : 'none';
      }
    }
  };
  
  /**
   * Toggle the state of the checkbox.
   * @private
   */
  Blockly.FieldCheckbox.prototype.showEditor_ = function() {
    var newState = !this.state_;
    if (this.sourceBlock_) {
      // Call any validation function, and allow it to override.
      newState = this.callValidator(newState);
    }
    if (newState !== null) {
      this.setValue(String(newState).toUpperCase());
    }
  };
  