A symbol naming a definer.
A list representing the parameters of a name dspec.
Forms evaluated to yield a dspec.
is useful when you add a new way of making existing definitions with a new defining form that expands into a system-provided defining form. The dspec system should consider the new and system-provided definers as variant forms of the same dspec class.
is used to convert one of them to the other during canonicalization by canonicalize-dspec.
LispWorks User Guide and Reference Manual - 21 Dec 2011