@function linear-gradient($pos, $gradients…) {

$type: linear;
$pos-type: type-of(nth($pos, 1));

// if $pos doesn't exist, fix $gradient
@if ($pos-type == color) or (nth($pos, 1) == "transparent")  {
  $gradients: zip($pos $gradients);
  $pos: false;
}

$type-gradient: $type, $pos, $gradients;
@return $type-gradient;

}