SETF-FUNCTIONS-AGAINSETF functions to the language has left some lingering questions:
- Whether (FBOUNDP '(SETF <name>)) is supposed to be true of <name>s that have SETF methods (as defined with DEFSETF or DEFINE-SETF-METHOD) defined, or only <name>s where there are globally defined functions named (SETF <name>). (Issue #17 from Loosemore's list.)
- Whether DEFSTRUCT is required to generate SETF functions, or required to generate SETF methods, or whether this is unspecified. (Issue #19)
- Whether SETF places defined in the standard are required to be implemented by SETF functions, by SETF methods, or whether this is unspecified. (Issue #20)
- Whether it is permissible for a <name> to have both a SETF method defined via DEFSETF or DEFINE-SETF-METHOD, and an associated SETF function at the same time.
FBOUNDP '(SETF <name>)) must return true if and only if there is a function named (SETF <name>) defined. It must return NIL if <name> has a SETF method defined but not a SETF function.
(2) Clarify that it is unspecified whether DEFSTRUCT generates SETF methods or SETF functions for non-:READ-ONLY slot accessors.
(3) Clarify that, unless a SETF function is explicitly documented in the standard, it is unspecified whether SETF places defined in the standard must be implemented as SETF methods or SETF functions. In combination with item (1), this implies that it is unspecified whether (SETF <name>) is FBOUNDP for these standard SETF places.
(4) Clarify that it is possible, but generally not very useful, to have both a SETF method and a SETF function defined for the same name.
SETF methods (and not SETF functions) to implement DEFSTRUCT accessors and the standard SETF places. In most implementations, the namespaces for SETF methods and SETF functions are disjoint.SETF places must be implemented as SETF functions or as SETF methods, instead of leaving it explicitly vague. See also issue SETF-OF-APPLY for one particular case (AREF) where it seems like a good idea to specify that the SETF place must be implemented as a SETF function.