// Private function for linear-gradient-parser
@function _linear-angle-parser($image, $first-val, $prefix, $suffix) {
    $offset: null;
    $unit-short: str-slice($first-val, str-length($first-val) - 2, str-length($first-val));
    $unit-long: str-slice($first-val, str-length($first-val) - 3, str-length($first-val));

    @if ($unit-long == "grad") or
      ($unit-long == "turn") {
        $offset: if($unit-long == "grad", -100grad * 3, -0.75turn);
    } @else if ($unit-short == "deg") or
           ($unit-short == "rad") {
        $offset: if($unit-short == "deg", -90 * 3, 1.6rad);
    }

    @if $offset {
        $num: _str-to-num($first-val);

        @return (
            webkit-image: -webkit- + $prefix + ($offset - $num) + $suffix,
            spec-image: $image
        );
    }
}