Function: defsetf

defsetf is a macro defined in cl.el.gz.

Signature

(defsetf NAME [FUNC | ARGLIST (STORE) BODY...])

Documentation

Define a setf method.

This macro is an easy-to-use substitute for define-setf-expander that works well for simple place forms.

In the simple defsetf form, setfs of the form (setf (NAME ARGS...) VAL) are transformed to function or macro calls of the form (FUNC ARGS... VAL). For example:

  (defsetf aref aset)

You can replace this form with gv-define-simple-setter.

Alternate form: (defsetf NAME ARGLIST (STORE) BODY...).

Here, the above setf call is expanded by binding the argument forms ARGS according to ARGLIST, binding the value form VAL to STORE, then executing BODY, which must return a Lisp form that does the necessary setf operation. Actually, ARGLIST and STORE may be bound to temporary variables which are introduced automatically to preserve proper execution order of the arguments. For example:

  (defsetf nth (n x) (v) `(setcar (nthcdr ,n ,x) ,v))

You can replace this form with gv-define-setter.

Probably introduced at or before Emacs version 24.3.

Source Code

;; Defined in /usr/src/emacs/lisp/obsolete/cl.el.gz
(defmacro defsetf (name arg1 &rest args)
  "Define a `setf' method.
This macro is an easy-to-use substitute for `define-setf-expander'
that works well for simple place forms.

In the simple `defsetf' form, `setf's of the form (setf (NAME
ARGS...) VAL) are transformed to function or macro calls of the
form (FUNC ARGS... VAL).  For example:

  (defsetf aref aset)

You can replace this form with `gv-define-simple-setter'.

Alternate form: (defsetf NAME ARGLIST (STORE) BODY...).

Here, the above `setf' call is expanded by binding the argument
forms ARGS according to ARGLIST, binding the value form VAL to
STORE, then executing BODY, which must return a Lisp form that
does the necessary `setf' operation.  Actually, ARGLIST and STORE
may be bound to temporary variables which are introduced
automatically to preserve proper execution order of the arguments.
For example:

  (defsetf nth (n x) (v) \\=`(setcar (nthcdr ,n ,x) ,v))

You can replace this form with `gv-define-setter'.

\(fn NAME [FUNC | ARGLIST (STORE) BODY...])"
  (declare (debug
            (&define name
                     [&or [symbolp &optional stringp]
                          [cl-lambda-list (symbolp)]]
                     cl-declarations-or-string def-body)))
  (if (and (listp arg1) (consp args))
      ;; Like `gv-define-setter' but with `cl-function'.
      `(gv-define-expander ,name
         (lambda (do &rest args)
           (gv--defsetter ',name
                          (cl-function
                           (lambda (,@(car args) ,@arg1) ,@(cdr args)))
			  do args)))
    `(gv-define-simple-setter ,name ,arg1 ,(car args))))