Exceptions are objects that are thrown in the event of some exceptional (or unexpected) condition or error and are used to describe the condition or error encountered. Standard errors, such as null object references and division by zero, are typically thrown by the runtime system. These types of errors could occur anywhere in an application, and you can include catch clauses in any executable script to try to recover from these errors.
There are also exceptional conditions that do not immediately result in runtime errors. These exceptions typically occur during execution of a function or a user-event script. To signal these exceptions, you create user objects that inherit from the PowerScript Exception class. You can associate a user-defined exception with a function or user event in the prototype for the method.
For example, a user-defined exception might be created to indicate that a file cannot be found. You could declare this exception in the prototype for a function that is supposed to open the file. To catch this condition, you must instantiate the user-defined exception object and then throw the exception instance in the method script.
