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13.11.2.4 Previewing a Message

Displays a list of all the applicable message-handlers for a message sent to an instance of a particular class. The level of indentation indicates the number of times a handler is shadowed, and lines connect the beginning and ending portions of the execution of a handler if it encloses shadowed handlers. The right double-angle brackets indicate the beginning of handler execution, and the left double-angle brackets indicate the end of handler execution. Message arguments are not necessary for a preview since they do not dictate handler applicability.

Syntax

(preview-send <class-name> <message-name>)

Example

For the example in section 9.5.3, the output would be:

CLIPS> (preview-send USER my-message)
>> my-message around in class USER
| >> my-message around in class OBJECT
| | >> my-message before in class USER
| | << my-message before in class USER
| | >> my-message before in class OBJECT
| | << my-message before in class OBJECT
| | >> my-message primary in class USER
| | | >> my-message primary in class OBJECT
| | | << my-message primary in class OBJECT
| | << my-message primary in class USER
| | >> my-message after in class OBJECT
| | << my-message after in class OBJECT
| | >> my-message after in class USER
| | << my-message after in class USER
| << my-message around in class OBJECT
<< my-message around in class USER
CLIPS>


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