No cl-lib replacement for define-modify-macro?

No cl-lib replacement for define-modify-macro?

[Glenn Morris]

It seems that there is no cl-lib replacement for cl.el's define-modify-macro.
(I can't really see anything in gv.el that would replace it either.)
Is that intentional (because it is believed to be unused)?
It looks like cl-define-modify-macro would have exactly the same
definition as define-modify-macro, so I can't see a reason not to simply
move it to cl-lib.el and add an alias in cl.el.

Re: No cl-lib replacement for define-modify-macro?

[Stefan Monnier]

> It seems that there is no cl-lib replacement for cl.el's define-modify-macro.
> (I can't really see anything in gv.el that would replace it either.)

The replacement is gv-letplace.


        Stefan

Re: No cl-lib replacement for define-modify-macro?

[Glenn Morris]

Stefan Monnier wrote:

> The replacement is gv-letplace.

How do I write:

(define-modify-macro incf (&optional (n 1)) +)

using gv-letplace? (Forget about the "&optional" bit if necessary.)

Re: No cl-lib replacement for define-modify-macro?

[Stefan Monnier]

>> The replacement is gv-letplace.
> How do I write:
> (define-modify-macro incf (&optional (n 1)) +)
> using gv-letplace? (Forget about the "&optional" bit if necessary.)

Guaranteed 100% untested:

   (defmacro incf (place &optional n)
     (gv-letplace (getter setter) place
       (macroexp-let2 nil v (or n 1)
         (funcall setter `(+ ,v ,getter)))))


-- Stefan