// Casts a string into a number (integer only)
// @access private
// @param {String} $value - Value to be parsed
// @return {Number}
// @author @HugoGiraudel - Simplified by @kaelig to only convert unsigned integers
// @link http://hugogiraudel.com/2014/01/15/sass-string-to-number/
@function _to-number($value) {
  $result: 0;
  $digits: 0;
  $numbers: ('0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9);

  @for $i from 1 through str-length($value) {
    $character: str-slice($value, $i, $i);

    @if not map-get($numbers, $character) {
      @return false;
    }

    @if ($digits == 0) {
      $result: $result * 10 + map-get($numbers, $character);
    } @else {
      $digits: $digits * 10;
      $result: $result + map-get($numbers, $character) / $digits;
    }
  }

  @return $result;
}