Automatic em-calc mixins for Sass and Less (requires up-to-date compilers)

em-calc.less

@font-context: 16;

.em-calc(@target, @property, @context: @font-context) {
    .loop(length(@target));
    .loop(@i) when (@i > 0) {
        .loop(@i - 1);
        @{property}+_: (extract(@target, @i) / @context) + 0em;
    }
}

em-calc.scss

$font-context: 16;

@function em-calculation($target, $context: $font-context) {
    @return ($target / $context) + 0em;
}

@mixin em-calc($list, $property, $context: 16) {
  $values: ();
  @each $i in $list {
    $values: append($values, em-calculation($i, $context));
  }
  #{$property}: $values; 
}