Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.9)
// Compass (v1.0.1)
// ----

@function selector-to-string($selector: "") {
  @if $selector == "" {
    $selector: &;
  }
  $selector-length: str-length(#{$selector});
  @return #{str-slice(#{$selector}, 1, $selector-length)};
}


x {
  content: "#{selector-to-string()}";
}

y {
  content: "#{selector-to-string('.container')}";
}

%extend {
  width: 100%;
  
  &-child {
    $this: selector-to-string();
    font-size: 16px;
    
    &--red {
      @extend #{$this};
      color: red;
    }
    
    &--blue {
      @extend #{$this};
      color: blue;
    }
  }
}

.test {
  @extend %extend;
  
  &-a {
    @extend %extend-child--red;
  }
  
  &-b {
    @extend %extend-child--blue;
  }
}

SassMeister-output.css

x {
  content: "x";
}

y {
  content: ".container";
}

.test {
  width: 100%;
}
.test-a, .test-b {
  font-size: 16px;
}
.test-a {
  color: red;
}
.test-b {
  color: blue;
}