Classical mixin inheritance in Sass

_inheritance.sass

$global_store: ()

= override($args:(), $is_child:true)
  @if $is_child
    $global_store: () !global
  $global_store: map-merge($global_store, $args) !global

= default($key_or_map, $value:null)
  @if $value
    +store-default($key_or_map, $value)
  @else
    @each $key, $value in $key_or_map
      +store-default($key, $value)

= store-default($key, $value)
  @if map-has-key($global_store, $key)
  @else
    $global_store: map-merge($global_store, ($key: $value)) !global

@function fetch($key)
  @return map-get($global_store, $key)

@lifeiscontent Hmm. Belated thanks. Figures that it was too good to be true. Had fun experimenting, though.