The generic function compute-discriminating-function returns the discriminator as specified in AMOP.
However, there are two discrepancies with the AMOP behavior:
compute-applicable-methods-using-classes
, since this is not implemented.add-method
does not call compute-discriminating-function. Instead, it is called when the generic function is called. This is more efficient than calling compute-discriminating-function each time add-method is called.LispWorks User Guide and Reference Manual - 20 Sep 2017