My first Lisp macro; is it leaking?

Question

I worked through Practical General Lisp , and as an exercise, it was decided to write a macro to determine if a number is several other numbers:

(defmacro multp (value factor)
`(= (rem ,value ,factor) 0))

so that: (multp 40 10) evaluates to true while (multp 40 13) not

The question is, how is this macro leak ? Also this "good" Lisp? Is there an existing function / macro that I could use?

Answer 1

Siebel ( ) , . value, factor , rem .

Lisp, .

(defun multp (value factor)
  (zerop (rem value factor)))

. ( zerop. , , , , - , - , , (= ... 0) )

Answer 2

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Answer 3

, , :

(flet ((= (&rest args) nil))
  (multp 40 10))

NIL... , ANSI CL , CL: =, .

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Answer 4

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(defmacro ana-and (&rest forms)
  (loop for form in (reverse forms)
        for completion = form then `(let ((it ,form))
                                      (when it
                                       ,completion))
        finally (return completion)))

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