The operations described in this section provide access to the constraint-checking services provided by FRSs. Note that these operations should be sensitive to the behaviors :constraint-checking-time and :constraint-report-time, as described in Section 4.
return-type argument are: :boolean meaning meaning when one or more violations occur return t; :string meaning when one or more violations occur return a string explaining the violation(s); and :struct meaning when one or more violation(s) occur return a list of defstructs whose fields explain the violation(s). The default value of return-type is :boolean. If no violation occurs then all constraint-checking functions return nil.
frame-violations frame &key kb return-type
slot-violations frame slot &key values kb return-type