code: function() {
      this.jsonInit({
        "message0": "%1 %2",
        "args0": [
          {
            "type": "field_dropdown",
            "name": "OP",
            "options": [
              [Blockly.Msg.MATH_TRIG_SIN, 'SIN'],
              [Blockly.Msg.MATH_TRIG_COS, 'COS'],
              [Blockly.Msg.MATH_TRIG_TAN, 'TAN'],
              [Blockly.Msg.MATH_TRIG_ASIN, 'ASIN'],
              [Blockly.Msg.MATH_TRIG_ACOS, 'ACOS'],
              [Blockly.Msg.MATH_TRIG_ATAN, 'ATAN']
            ]
          },
          {
            "type": "input_value",
            "name": "NUM",
            "check": "Number"
          }
        ],
        "output": "Number",
        "colour": Blockly.Blocks.math.HUE,
        "helpUrl": Blockly.Msg.MATH_TRIG_HELPURL
      });
      // Assign 'this' to a variable for use in the tooltip closure below.
      var thisBlock = this;
      this.setTooltip(function() {
        var mode = thisBlock.getFieldValue('OP');
        var TOOLTIPS = {
          'SIN': Blockly.Msg.MATH_TRIG_TOOLTIP_SIN,
          'COS': Blockly.Msg.MATH_TRIG_TOOLTIP_COS,
          'TAN': Blockly.Msg.MATH_TRIG_TOOLTIP_TAN,
          'ASIN': Blockly.Msg.MATH_TRIG_TOOLTIP_ASIN,
          'ACOS': Blockly.Msg.MATH_TRIG_TOOLTIP_ACOS,
          'ATAN': Blockly.Msg.MATH_TRIG_TOOLTIP_ATAN
        };
        return TOOLTIPS[mode];
      });
    }
docs: Block for trigonometry operators.
  @this Blockly.Block