Generated by SassMeister.com.

SassMeister-input-HTML.html

<ul>
  <li class="ul_x">1111111</li>
  <li>2222222</li>
  <li>3333333</li>
</ul>

SassMeister-input.scss

// ----
// Sass (v3.4.25)
// Compass (v1.0.3)
// ----

$ppp:10px;
ul{ 
  background: yellow;
  li {
    &:hover{
      color:red;
    }
    color: green;
  }
  .#{&}_x{
    color: red; 
  }
  border:solid 1px;
  border-radius: $ppp;
}

.a{
  color:red;
}
.b{
  @extend .a;
  font-size:10px;
}
@function get-width($n) {
  @return '#{100/$n}%';
}
@mixin c{
  color:red;
  font-size: 10px;
}
.d{
  @include c;
  color:green;
  width: get-width(3);
}

SassMeister-output.css

ul {
  background: yellow;
  border: solid 1px;
  border-radius: 10px;
}
ul li {
  color: green;
}
ul li:hover {
  color: red;
}
ul .ul_x {
  color: red;
}

.a, .b {
  color: red;
}

.b {
  font-size: 10px;
}

.d {
  color: red;
  font-size: 10px;
  color: green;
  width: "33.33333%";
}

SassMeister-rendered.html

<ul>
  <li class="ul_x">1111111</li>
  <li>2222222</li>
  <li>3333333</li>
</ul>