Mixin Position

gistfile1.scss

@mixin absolute($args) {
    /**
     * List of offsets to check for in $args
     */
    $offsets: top right bottom left;

    /**
     * We loop through $offsets to deal with them one by one
     */
    @each $o in $offsets {

        /**
         * If current offset found in $args
         * assigns its index to $i
         * Or `false` if not found
         */
        $i: index($args, $o);

        /**
         * Now we do the verifications
         * 1. Is the offset listed in $args? (not false)
         * 2. Is the offset value within the list range?
         * 3. Is the offset value valid?
         */
        @if $i                                      /* 1 */
        and $i + 1 <= length($args)                 /* 2 */
        and type-of( nth($args, $i + 1) ) == number /* 3 */ {

            /**
             * If everything is okay
             * We assign the according value to the current offset
             */
            #{$o}: nth($args, $i + 1);
        }
    }
}