Deprecation Warning: Using / for division outside of calc() is deprecated and will be removed in Dart Sass 2.0.0

Question

In these functions I compile rem to px and em to px:

$base: 16 !default;

@function scut-strip-unit($num) {
  @return $num / ($num * 0 + 1);
}

@function rem($pixels) {
  @return scut-strip-unit($pixels) / $base * 1rem;
}

@function em($pixels, $context: $base) {
  @return #{$pixels / $context}em;
}

But with Sass v1.49, we are facing this error:

Error
Deprecation Warning: Using / for division outside of calc() is deprecated and will be removed in Dart Sass 2.0.0.    

Recommendation: math.div(scut-strip-unit($pixels), $base) or calc(scut-strip-unit($pixels) / $base)    

More info and automated migrator: https://sass-lang.com/d/slash-div 
   
  ╷
8 │ @return scut-strip-unit($pixels) / $base * 1rem;

Answer 1

To avoid using sass:math, you may just use

calc(scut-strip-unit($pixels) / $base)

Answer 2

If you need a bunch of constants the best approach is usually to have a bunch of constants: you are going to need to wire in the names of things anyway: there's nothing to be gained by (f '<name>) or (m <name>) instead of just <name> unless you want <name> to refer to something else as well. If you want those constants all defined in one place then that's easy. I assume (based on defconst) you are writing elisp, and if so a macro like this will serve:

(defmacro define-constants (&rest forms)
  `(progn
     ,@(mapcar (lambda (form)
                 `(defconst ,@form))
               forms)))

And now

(define-constants
  (foo 1)
  (bar 2)
  ...)

(Disclaimer: I have not kept up with the changes in elisp in the last 20 years or more: the above works on Emacs 27.2.)

If you're using Common Lisp or some other Lisp there are often better approaches.