Transient screens

A transient macro screen is used to process an application screen that has the following characteristics:

The application screen occurs unpredictably during the flow of the application. It might occur at several points or it might not occur at all.
The only action that needs to occur for the application screen is that it needs to be cleared.

An example of such an application screen is an error screen that the application displays when the user enters invalid data. This error screen appears at unpredictable times (whenever the user enters invalid data) and as a macro developer the only action that you want to take for this error screen is to clear it and to get the macro back on track.

When the macro runtime prepares to play back a macro, at the point where the macro runtime adds the names of entry screens to the runtime list of valid next screens, the macro runtime also adds the names of all macro screens marked as transient screens (if any) to the end of the list.

The names of these transient screens remain on the runtime list of valid next screens throughout the entire macro playback. Whenever the macro runtime adds the names of new candidate macro screens (from the <nextscreens> element of the current macro screen) to the list, the macro runtime adds these new candidate names ahead of the names of the transient screens, so that the names of the transient screens are always at the end of the list.

Whenever the macro runtime performs screen recognition, it evaluates the macro screens of all the names on the list in the usual way. If the macro runtime does not find a match to the application screen among the candidate macro screens whose names are on the list, then the macro runtime goes on down the list trying to match one of the transient macro screens named on the list to the application screen.

If the macro runtime matches one of the transient macro screens to the current application screen, then the macro runtime does not remove any names from the list. Instead, the macro runtime performs the actions in the transient macro screen (which should clear the unexpected application screen) and then goes back to the screen recognition process that it was pursuing when the unexpected application screen occurred.