title: SCSS Interpolation in mixin call
body: <p>I want to make a simple interpolation into a mixin call:</p>
  
  <pre><code>$models: "square", "square-green", "circle";
  $services: "facebook", "twitter", "linkedin", "gplus", "feed";
  
  @each $model in $models {
      @include all-#{$model}-sprites;
      @each $service in $services {
              #{$model}-#{$service} {
                  &amp;:hover{ @extend .#{$model}-#{$service}-hover;};
              }
      }
  }
  </code></pre>
  
  <blockquote>
    <p>error sass/soboo2.scss (Line 14: Invalid CSS after "  @include all-":
    expected "}", was "#{$model}-sprites;")</p>
  </blockquote>
  
  <p>I've also tried a few syntax variations that come across internet:</p>
  
  <pre><code>@include all-"#{$model}"-sprites;
  @include [all-#{$model}-sprites];
  @include [all-"#{$model}"-sprites];
  @include all-$model-sprites;
  </code></pre>
  
  <p>Doesn't work... any suggestions??</p>