Generated by SassMeister.com.

SassMeister-input-HTML.html

<div class="box">
  Box
</div>

<div class="box-plain">
  Box plain
</div>

<div class="box-fancy">
  Box fancy
</div>

SassMeister-input.scss

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

@mixin clearfix() {
    &:before,
    &:after {
        content: "";
        display: table;
    }
    &:after {
        clear: both;
    }
}

.row {
  @include clearfix;
}

.nav {
  @include clearfix;
}

SassMeister-output.css

.row:before, .row:after {
  content: "";
  display: table;
}
.row:after {
  clear: both;
}

.nav:before, .nav:after {
  content: "";
  display: table;
}
.nav:after {
  clear: both;
}

SassMeister-rendered.html

<div class="box">
  Box
</div>

<div class="box-plain">
  Box plain
</div>

<div class="box-fancy">
  Box fancy
</div>