+;;; Does this form look like something that we should add single-stepping
+;;; instrumentation for?
+(defun step-form-p (form)
+ (flet ((step-symbol-p (symbol)
+ (not (member (symbol-package symbol)
+ (load-time-value
+ ;; KLUDGE: packages we're not interested in
+ ;; stepping.
+ (mapcar #'find-package '(sb!c sb!int sb!impl
+ sb!kernel sb!pcl)))))))
+ (and *allow-instrumenting*
+ (policy *lexenv* (= insert-step-conditions 3))
+ (listp form)
+ (symbolp (car form))
+ (step-symbol-p (car form)))))
+