Error Escape Handler

 

    Special control flow for errors is perfomred an error escape handler that is called by the default exception handler. An error escape handler takes no arguments and must escape from the expression that raised the error.

• (error-escape-handler) returns the current error escape handler.
• (error-escape-handler f) sets the handler to f. The procedure f cannot invoke a full continuation that was created prior to the error, but it can invoke an escaping continuation.

Generally, the error escape handler is only called directly by an exception handler. To escape from a run-time error, use raise (see section 2.23) or error (see section 2.24) instead.

If an exception is raised while the error escape handler is executing, an error message is printed using a primitive error printer and the primitive error escape handler is invoked.