Exception classes

Cancel

This exception can be raised to abort an operation, such as in response to the user clicking a Cancel button. It is silently caught by the main event loop.

When writing code, you should keep the possibility of Cancel exceptions in mind, and make judicious use of try-finally to clean up after operations that could be cancelled part way through.

ApplicationError(message [, detail])

This exception can be raised to signal an error that should be reported to the user. It is caught by the main event loop and a suitable alert displayed.

The message should be a brief description of the error, including primary relevant information. The detail may be a longer discourse providing further information about the cause of the error and/or possible remedies. For example,

message:

"Unable to open the file 'InterestingStuff.txt'".

detail:

"Someone has spread peanut butter on the disk. Please clean it and try again."