title: Combining Sass mixin selectors
body: <p>I'm trying to figure out if it's at all possible to combine mixin selector strings. I don't believe this is possible in the context of my code, but I could very well be missing something!</p>
  
  <p>Let's say I have the following scss:</p>
  
  <pre><code>// Apply a set of rules to input form fields.
  @mixin input-form-fields {
      input:not([type="hidden"]),
      textarea {
          @content;
      }
  }
  
  // Apply a set of rules to button form fields.
  @mixin button-form-fields {
      button, button {
          @content;
      }
  }
  
  // Apply a set of rules to select form fields.
  @mixin select-form-fields {
      select {
          @content;
      }
  }
  
  // Apply a set of rules to all form fields.
  @mixin all-form-fields {
      @include input-form-fields {
          @content;
      }
      @include button-form-fields {
          @content;
      }
      @include select-form-fields {
          @content;
      }
  }
  </code></pre>
  
  <p>Basically the all-form-fields mixin will call other mixins, thus generating the same set of rules for different selectors.</p>
  
  <p>If I compile the following code:</p>
  
  <pre><code>@include all-form-fields {
      margin-bottom: .5em;
  }
  </code></pre>
  
  <p>I would get something like: </p>
  
  <pre><code>input:not([type="hidden"]),
  textarea {
    margin-bottom: .5em;
  }
  
  button, 
  .button {
    margin-bottom: .5em;
  }
  
  select {
    margin-bottom: .5em;
  }
  </code></pre>
  
  <p>This is not ideal, I would love it if I could combine those selectors. </p>
  
  <p>Does anyone have any ideas on how I could possibly combine the selector strings returned by the 3 different mixins?</p>