Compass "scale" mixin for calculating ems

scale.scss

// for the life of me, I can't track down the original place where I found this.

// syntax for scale mixin is like this
// property, sizes in px, context
//@include scale(padding, (16, 14, 12, 9), 20);
// 16px is default context size

@mixin scale($props, $sizes, $base: 16) {
	$values: ();
	$sublists: false;
	@each $s in $sizes {
		// unwrap lists for values that have multiple list of values such as text-shadow
		@if type-of($s) == list {
			$sublists: true;
			$vv: ();
			@each $ss in $s {
				$vv: append($vv, if(type-of($ss) == number, #{$ss / $base}em, $ss));
			}
			$values: append($values, join((), $vv));
		} @else {
			$values: append($values, if(type-of($s) == number, #{$s / $base}em, $s));
			// $values: append($values, #{$s}px);
		}
	}
	$value: join((), $values, if($sublists, comma, space));
	@each $prop in $props { #{$prop}: $value }
}