For rapid prototyping purposes in common-lisp it would be convenient to be able to easily function-modify an object in an arbitrary data structure. This would seem to involve calling an arbitrary function on a place in the data structure, replacing the object at that place with the result of the function call. Common-lisp has a number of specialized modification macros (eg, incf, push, getf, etc) for particular types of objects, and setf for generalized place modification (eg, setf-second, setf-aref, setf-gethash, etc). But rather than inventing new specialized macros for other object types, or having to mentally consider the characteristics of each macro (slowing down development), it might be nice to have a generalized setf-like modification capability that was simpler to use than setf. For example, instead of (setf (second (getf plist indicator)) (1+ (second (getf plist indicator)))) or (incf (second (getf plist indicator))), one might write (callf (second (getf plist indicator)) #'1+), using any of the normal one argument functions (or lambda-expression) provided by common-lisp or the user. Here is an attempt at code:

(defun call (object function) (funcall function object)) (define-modify-macro callf (&rest args) call) 

Will something like this work for all general cases, and can it actually simplify code in practice?