Variable Tree and Watch Window

When the program is halted at a breakpoint, you can examine the state of your runtime structures and evaluate ER variables using the Variable Tree and Variable Watch windows.

The Variable Tree and Watch window consists of two panes. The left pane is the Variable Tree pane. It contains a tree structure that lists the variable types as parent nodes and the variables of each variable type as child nodes. The variables displayed are those that are in scope of the currently displayed event in the Event Rule window. The right pane is the Watch pane. It displays variables you select and their most recently known values. Each variable is identified by its category, name, and the Id of the form, if any, to which it belongs. You can add a variable to the Watch pane by double-clicking the desired variable in the Variable Tree, or you can right click on the variable in the Variable Tree and select "Watch Variable" to add it to the Watch list.

You can change the value of variables while you are debugging an application, in order to better understand what effect that might have on subsequent ER execution. This is a powerful feature, which can also mess up your program execution and create unwanted side effects. Use it carefully. To change the value of a variable, the application must be stopped at a line of ER. Double-click the variable in the Watch pane and enter a different value. If the ER engine running the application accepts the new value, the new value appears in the Watch pane. If you enter an inappropriate value (for example, you change a numeric value to an alpha value) the new value is not set and the value is not changed. In any case, the Debugger displays the actual, resulting variable value.

These special values are displayed for variables:

• blank

  The value for the variable contains only blanks. This value applies to string and character types only.

• null

  The variable has no value, or a null or empty value.

• unknown

  The value for the variable could not be obtained from the runtime engine. When adding a variable to the watch list, the initial value is always unknown. The value is also unknown when the applications are not running, or when the variable is out of scope.

  Note: Variable inspection and modification is not available for debugging NERs and table ER.