Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.0.rc.1)
// Compass (v0.13.alpha.10)
// ----

$list-1: null;
$list-2: ();

@each $n in (1, 2, 3, 4) {
  $list-1: append($list-1, $n, comma);
  $list-2: append($list-2, $n, comma);
}

building lists programmatically {
    list-1: $list-1 == (1, 2, 3, 4);
    list-2: $list-2 == (1, 2, 3, 4);
}

SassMeister-output.css

building lists programmatically {
  list-1: false;
  list-2: true;
}