LESS. Is it possible to convert px to rem without mixins?

Question

css

Hello.
Interested in the possibility of automatic conversion to other units of measurement using parameterized variables.
For example, a variable of type is created @value(), and when you write a value in parentheses px, it gives the result in remto the property in which it is specified.
Something like:

.block {
  width: @value(100);
}

After compilation:

.block {
  width: 6.25rem;
}

Using mixins allows you to define only specific properties, but I'm interested in the possibility of universal application

Answer 1

There is no way with standard tools, in less it seems like there are no user functions, but you can add an extension to JS, on stackoverflow somewhere there was a similar question and this answer:

em: function(less, fontsize, basefontsize){
    if (less.functions.functionRegistry.get('ispixel')){
        basefontsize = (basefontsize) ? basefontsize.value : 16
        return fontsize.value/basefontsize+'em';
    }
}

.block {
    font-size: em(16px);
}

Answer 2

There really are no user-defined functions, but, as an option, you can take this thing:
And multiply by it in those places where you need to convert px to rem:

p {
    font-size: @rem * 50;
    border: @rem * 5 solid #000;
    padding: @rem * 10;

    /* В CSS получится
        font-size: 3.125rem;
        border: 0.3125rem solid #000;
        padding: 0.625rem;
    */
}

Link to codepen

Answer 3

Here is my Sass mixin.

$browser-context: 16

@function rem($pixels, $context: $browser-context)
  @return #{$pixels / $context}rem

Challenge:
In general, I recommend switching to Sass. After LESS, the Scss syntax will be more convenient.