Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.2.19)
// Compass (v0.12.6)
// ----

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

// ===============================================

// http://css-tricks.com/snippets/css/less-mixin-for-rem-font-sizing/

@mixin rem($property, $values...) {
  $max: length($values);
  $pxValues: '';
  $remValues: '';
	
	
	@if $property == fz {
		$property: font-size;
	} @else if $property == m {
		$property: margin;
	}	@else if $property == mt {
		$property: margin-top;
	}	@else if $property == mr {
		$property: margin-right;
	}	@else if $property == mb {
		$property: margin-bottom;
	}	@else if $property == ml {
		$property: margin-left;
	} @else if $property == p {
	 	$property: padding;
	 }	@else if $property == pt {
	 	$property: padding-top;
	 }	@else if $property == pr {
	 	$property: padding-right;
	 }	@else if $property == pb {
	 	$property: padding-bottom;
	 }	@else if $property == pl {
	 	$property: padding-left;
	 }

  @for $i from 1 through $max {
    $value: strip-unit(nth($values, $i));
    $pxValues: #{$pxValues + $value}px;

    @if $i < $max {
      $pxValues: #{$pxValues + " "};
    }
  } 

  @for $i from 1 through $max {
    $value: strip-unit(nth($values, $i));
    $remValues: #{$remValues + $value/16}rem;

    @if $i < $max {
      $remValues: #{$remValues + " "};
    }
  } 
  
  #{$property}: $pxValues; 
  #{$property}: $remValues; 
}

.test {
  @include rem(p,30,10,10);
  @include rem(fz,40);
}

.test-mt {
  @include rem(mt,20);
}

.test-m {
  @include rem(m,30,10,10);
}

SassMeister-output.css

.test {
  padding: 30px 10px 10px;
  padding: 1.875rem 0.625rem 0.625rem;
  font-size: 40px;
  font-size: 2.5rem;
}

.test-mt {
  margin-top: 20px;
  margin-top: 1.25rem;
}

.test-m {
  margin: 30px 10px 10px;
  margin: 1.875rem 0.625rem 0.625rem;
}