Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.4)
// Compass (v1.0.1)
// ----

@mixin corral($selector) {
  $context: &;
  $new-context: $context;
  $root-context: '';
  $selector-is-root-context: false;
  @if is-superselector('html', $selector) {
    $root-context: $selector;
    $selector-is-root-context: true;
  }
  @if $context {
    $new-context: ();
    @for $i from 1 through length($context) {
      $subcontext: nth($context, $i);
      $new-subcontext: ();
      @for $j from 1 through length($subcontext) {
        $bit: nth($subcontext, $j);
        $bit-is-root: is-superselector('html', $bit);
        @if $bit-is-root and $selector-is-root-context {
          $root-context: selector-unify($bit, $root-context);
        } @else {
          $new-subcontext: append($new-subcontext, $bit);
        }
      }
      $new-context: append($new-context, $new-subcontext);
    }
  }
  @at-root #{$root-context} #{$new-context} {
    @content;
  }
}

.my-container {
  color: blue;
  @include corral('html.touch') {
    color: green;
    .foo & {
      @include corral('html.mobile') {
        &.my-thing {
          color: red;
        }
      }
    }
  }
}

SassMeister-output.css

.my-container {
  color: blue;
}
html.touch .my-container {
  color: green;
}
html.touch.mobile .foo .my-container.my-thing {
  color: red;
}