django-compass-mixins/compass_mixins/static/compass/functions/_constants.scss

// 
// A partial implementation of the Ruby constants functions from Compass:
// https://github.com/Compass/compass/blob/stable/lib/compass/sass_extensions/functions/constants.rb
// 

@function opposite-position($from) {
    @if ($from == top) {
        @return bottom;
    } @else if ($from == bottom) {
        @return top;
    } @else if ($from == left) {
        @return right;
    } @else if ($from == right) {
        @return left;
    } @else if ($from == center) {
        @return center;
    }
}