问题
I want to find the name of the message that triggered the MNU , how do I do that ?
For example if I do
Transcript explode .
This will trigger a MNU because method explode does not exist but how do I find that the name of the message that triggered MNU is "explode" ?
回答1:
If I DoIt that, I get a debugger. The title there is
MessageNotUnderstood: ThreadSafeTranscript>>explode
When I select the first element, I get to see the doesNotUnderstand: aMessage, where aMessage is the message
回答2:
Try this:
[Transcript explode] on: MessageNotUnderstood do: [:ex| ex message selector]
The exception's message is an instance of Message. It understands selector arguments etc.
Remember that the exception is an epiphenomenon. The VM actually sends doesNotUnderstand: aMessage when a message is not understood, and the doesNotUnderstand: method in Object raises the exception. The argument to doesNotUnderstand: is a message, and is of curse the same as that in the exception. That means you can implement your own doesNotUnderstand: message in your own class if you have special requirements.
来源：https://stackoverflow.com/questions/24831610/how-to-find-which-was-the-wrong-message-in-a-message-not-understood-message