Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.14)
// Compass (v1.0.0.rc.1)
// ----

$root-font:(
	color: #222,
	font-family: Open Sans,
	font-size: 10,
	font-weight: normal,
	line-height: 1.6,
	modular-base--primary: 18,
	modular-base--secondary: 620,
	modular-multiplier: 1.3,
);

@function size(
  $exponent,
  $multiplier: map-get($root-font, modular-multiplier),
  $base--primary: map-get($root-font, modular-base--primary),
  $base--secondary: map-get($root-font, modular-base--secondary)
) {
  $value: $multiplier * $base--primary;
  @if $exponent > 1 {
    $value: $multiplier * $base--primary;
    $secondary: $multiplier * $base--secondary;

    @if $exponent % 2 == 0 {
      $value: $multiplier * $base--secondary;
    }
    @for $i from 2 through $exponent {
      $value: $value * $multiplier;
    }
  }
  @if $exponent < 1 {
    $value: $multiplier * $base--primary;

    @for $i from 0 through -$exponent {
      $value: $value / $multiplier;
    }
  }
  @return $value;
}

@function em($value, $context: map-get($root-font, font-size)) {
	@return ($value / $context * 1em);
}

// show numbers
h1 {
  font-size: size(-3);
  font-size: size(-2);
  font-size: size(-1);
  font-size: size(1);
  font-size: size(2);
  font-size: size(3);
}

// change some stuff
h2 {
  // changed modifier
  font-size: size(2, 1.2);
  
  // changed base multiplier
  font-size: em(size(2,20));
}

// for realsies
div {
  font-size: em(26.17924);
  font-size: em(size(2));
  
  h1 {
    font-size: em(42.35801,26.17924);
    font-size: em(size(3),size(2));
  }
}

SassMeister-output.css

h1 {
  font-size: 8.19299;
  font-size: 10.65089;
  font-size: 13.84615;
  font-size: 23.4;
  font-size: 1047.8;
  font-size: 39.546;
}

h2 {
  font-size: 892.8;
  font-size: 24800em;
}

div {
  font-size: 2.61792em;
  font-size: 104.78em;
}
div h1 {
  font-size: 1.618em;
  font-size: 0.03774em;
}