Tracing SETF on structures

[jmccarth%stimpy@cs.umass.edu (Joe McCarthy)]

Howdy,

We have a structure defined by

(DEFSTRUCT NP-RECORD
  ...
  RELATED-NP
  ...)

and we would like to be able to set up tracing so that we can see
whenever the RELATED-NP field of an NP-RECORD is changed, i.e.,,
whenever a form such as

	(SETF (NP-RECORD-RELATED-NP <np-record>)
              <new-value>)

is executed.  In Section 5.4 of the Allegro CL Common Lisp User Guide
(Version 4.1, March 1992, page 5-29), the following example is given:

	(trace ((method (setf slot-1) (t baz))))
	(trace ((method foo :before (integer))))
	(trace ((method foo :after (integer))))

Unfortunately, I am unable to interpret how I can use this example to
set up the tracing I want.  In particular, I'm not sure what SLOT-1,
and (T BAZ) mean.

Taking a guess at a mapping, I tried the following

	(trace ((method (setf related-np) (t np-record))))

but this yielded:

Error: (METHOD (SETF RELATED-NP) (T NP-RECORD)) does not have a function
       definition

Can anyone help me figure out how to set up the desired tracing?

Thanks, in advance, for any assistance.

Joe.