Generated by SassMeister.com.

SassMeister-input.scss

// ----
// libsass (v3.2.5)
// ----

$cols: 3;

@for $i from 1 through $cols {
    $index: index($cols, $i);
    
    .col---1 {
      index: $index;
      content: $i;
    }
}

SassMeister-output.css

.col---1 {
  content: 1;
}

.col---1 {
  content: 2;
}

.col---1 {
  index: 1;
  content: 3;
}