An Introduction to FeedDemo

FeedDemo consists of two parts:

· FeedDemo.app - an application that simulates a data feed module.

· feed_demo(x) - an external Questor function that retrieves data from FeedDemo.app

The source code for the app is in the FeedDemo folder and the source code for the function is in the FeedDemoFunction folder.

Note 1: To compile the function, use the target 'xqro' instead of 'bundle'.

Note 2: The FeedDemo and the FeedDemoFunction folders must be located in the same folder.

Implementation Details

The FeedDemo application checks in a new Distributed Objects (DO) server when is launched. The feed_demo function (in Questor) will look for this server when it is first executed. The feed_demo function retrieves data from the application using DO messages. Please refer to the QScript Reference for details how to write external functions for Questor.

How to Use

1. Start the FeedDemo.app.

2. Load the external function feed_demo() into Questor by opening the feed_demo.xqro file in Questor. (Just double-click on the file in Workspace)

3. You can verify that the function is loaded into Questor by using the External Functions tool in the Questor ToolBox.

4. Open a new worksheet and type the formula 
= feed_demo("A") 
into a cell.

5. Each time the worksheet is recalculated, the value for the variable A in the FeedDemo application will be used as the cell value.

6. Each time the value for variable A is changed, the worksheet will recalculate and paragraph 5 (above) will apply.