I have a need to generate a lot of similar functions, and I do not want to cut and paste the code. I want to generate the functions with code. This seems to be what macros are for in emacs lisp.
As a prototype example, we will make functions that raise a number to a power. We want functions like power-3 and power-4 that raise numbers to the third and fourth powers. We will define functions like this for the numbers 0-9.
Here we define the macro. i do not want to get into the nitty gritty details of macro definitions here.
(defmacro make-power-n (n) `(defun ,(intern (format "power-%s" n)) (arg) (expt arg ,n))) (make-power-n 4) (power-4 4)
Now we use the macro and mapcar on it onto a list of numbers. We have to eval the macro in the mapcar lambda function.
(defmacro make-power-n (n) `(defun ,(intern (format "power-%s" n)) (arg) (expt arg ,n))) (mapcar (lambda (x) (eval `(make-power-n ,x))) '(0 1 2 3 4 5 6 7 8 9)) ;; example of a few functions (list (power-0 3) (power-1 3) (power-2 3))
It works! We created 10 functions in a little bit of code.
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