Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.14)
// Compass (v1.0.0.rc.1)
// ----

// attribute used instead of `class`
$class-attr:  'data-g';

// return attribute selector
@function g($class) {
  @return '[#{$class-attr}~="#{$class}"]';
}

@mixin g($class, $direct: false) {
  #{if($direct, '&', '')}#{g($class)} {
    @content;
  }
}
@mixin _g($class) {
  @include g($class, true) {
    @content;
  }
}

a {
 @include _g(foo) {
   color: blue;
 }
}
a {
 @include _g(foo) {
   color: yellow;
 }
}

a {
 @include _g(foo) {
   @include _g(bar) {
     color: green;
   }
 }
}

SassMeister-output.css

a[data-g~="foo"] {
  color: blue;
}

a[data-g~="foo"] {
  color: yellow;
}

a[data-g~="foo"][data-g~="bar"] {
  color: green;
}