<h1>SCSS selector mixin (+function)</h2>
<pre>
<span>//    Selector map allowing labels as reference</span> 
$selector-map: ( 
  'main'   : '.main-nav', 
  'aside'  : '.sidebar', 
  'login'  : '.user-account-area'
);


<span>//    Function and mixin to return selectors</span>    
@function selector($selector-keys...) {
    $selector-list: ();
    @each $key, $value in $selector-keys { 
      $selctor-value: map-get($selector-map, $key);
      $selector-list: append($selector-list, unquote($selctor-value or $key), comma); 
    }
    @return $selector-list;
}
@mixin selector($selector-keys...) { #{selector($selector-keys...)} { @content;} }


<span>//    Use examples:
//    Interpolated function call</span>
#{selector(login)} { content: 'A'; }

<span>//    Mixin include with passed @content</span>
@include selector(main) { content: 'B'; }

<span>//    Pass multiple selectors if you please</span>
@include selector(main, aside) { content: 'C'; }

<span>//    Non mapped selectors works too</span>
@include selector('.not-in-map-selector') { content: 'D'; }

<span>//    ...So does variables</span>
$selector: 'body > div';
@include selector($selector) { content: 'E'; }
</pre>

<pre>
<span>//    Output</span>
.user-account-area   { content: 'A'; }
.main-nav            { content: 'B'; }
.main-nav, .sidebar  { content: 'C'; }
.not-in-map-selector { content: 'D'; }
body > div           { content: 'E'; }
</pre>
<p>In response to <a href="https://css-tricks.com/snippets/sass/use-sass-variable-selector" target="_blank">Use a Sass Variable for a Selector</a></p>    

//    Selector map allowing labels as reference 
$selector-map: ( 
  'main'   : '.main-nav', 
  'aside'  : '.sidebar', 
  'login'  : '.user-account-area'
);


//    Function and mixin to return selectors    
@function selector($selector-keys...) {
    $selector-list: ();
    @each $key, $value in $selector-keys { 
      $selctor-value: map-get($selector-map, $key);
      $selector-list: append($selector-list, unquote($selctor-value or $key), comma); 
    }
    @return $selector-list;
}
@mixin selector($selector-keys...) { #{selector($selector-keys...)} { @content;} }


//    Use examples:
//    Interpolated function call
#{selector(login)} { content: 'A'; }

//    Mixin include with passed @content
@include selector(main) { content: 'B'; }

//    Pass multiple selectors if you please
@include selector(main, aside) { content: 'C'; }

//    Non mapped selectors works too
@include selector('.not-in-map-selector') { content: 'D'; }

//    ...So does variables
$selector: 'body > div';
@include selector($selector) { content: 'E'; }