6.6 Restarts

The debugger provides a way to signal any restart for which a handler is available at a given point in application execution. Restarts are part of the Dylan language's condition system, and are explained in chapter 7 of the DRM.

You can use the debugger to signal a restart if your application has entered the debugger due to a condition having been signalled but not handled, or due to it reaching a breakpoint. You cannot do so if the application has paused because you used Application > Pause. (Use Application > Resume to restart your application in that case.)

To select a restart to be signalled, choose Thread > Continue..., which displays a dialog listing all available restarts.

For convenience, there are two other menu items for signalling <abort> restarts, which are defined to mean "terminate the current computation".

Thread > Abort signals the innermost available <abort> restart--that is, it aborts as little as possible--whereas Thread > Abort All signals the outermost <abort> restart--that is, it aborts as much as possible.

Although the meaning of <abort> restarts is part of the Dylan language, your application must provide handlers to implement them. If you are using DUIM for your application's GUI, note that DUIM frames normally provide <abort> handlers in the event loop, so that aborting while processing an event will proceed to process the next event. See the DUIM documentation for start-frame and start-dialog.

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Getting Started with Functional Developer - 31 MAR 2000