sass-layout/_util.scss

@function is-percentage($number) {
  $string: inspect($number);
  $last-letter: str-slice($string, str-length($string), str-length($string));
  @return $last-letter == '%';
}

@function map-set($map, $key, $value) {
  $new: ($key: $value);
  @return map-merge($map, $new);
}

@mixin save-layout($node) {
  $node: save-layout($node);
}

@function save-layout($node) {
  $selector: map-get($node, selector);
  $global-frame-map: map-set($global-frame-map, $selector, $node) !global;
  @return $node;
}

@function get-layout($node) {
  @return map-get($global-frame-map, $node);
}

@function render-node($node) {
  $layout: map-get($global-frame-map, $node);
  @return (
  map-get($layout, width), 
  map-get($layout, height), 
  map-get($layout, top), 
  map-get($layout, left)
  );
}

@function layout-property($property-name, $layout) {
  @if map-get($layout, #{$property-name}) == null {
    $layout: map-set($layout, #{$property-name}, 0);
  }
  $property: map-get($layout, #{$property-name});
  @if length($property) == 1 { $property: ($property, $property, $property, $property); }
  @if length($property) == 2 { $property: join($property, $property); }
  @if length($property) == 3 { $property: join($property, nth($property, 2)); }
  @if map-get($layout, #{$property-name}-top) == null { $layout: map-set($layout, #{$property-name}-top, nth($property, 1)); }
  @if map-get($layout, #{$property-name}-right) == null { $layout: map-set($layout, #{$property-name}-right, nth($property, 2)); }
  @if map-get($layout, #{$property-name}-bottom) == null { $layout: map-set($layout, #{$property-name}-bottom, nth($property, 3)); }
  @if map-get($layout, #{$property-name}-left) == null { $layout: map-set($layout, #{$property-name}-left, nth($property, 4)); }
  @return $layout;
}

@function parent-selector($current-node) {
  $selector-list: nth(selector-parse($current-node), 1);
  $selector-length: length($selector-list);
  @if $selector-length < 2 {
    @return "";
  }
  $parent-selector: nth($selector-list, 1);
  @if $selector-length == 2 {
    @return $parent-selector;
  }
  @for $i from 2 through ($selector-length - 1){
    $parent-selector: selector-nest($parent-selector, nth($selector-list, $i));
  }
  @return #{$parent-selector};
}