BEM and Sass, without mixins or functions

To follow up on my previous BEM and Sass post, it’s actually possible to use an even simpler syntax without any mixins or functions at all.

This:

.block {
    $b: &;
    margin: 1em;
    &__element {
        color: red;
    }
    &--modifier {
        margin: 2em;
        #{$b} {
            &__element {
                color: blue;                    
            }    
        }
    }
}

Will output this:

.block {
  margin: 1em;
}
.block__element {
  color: red;
}
.block--modifier {
  margin: 2em;
}
.block--modifier .block__element {
  color: blue;
}