<===> input.scss
$map: (
    purple: foo,
    rgba(1,2,3,1): bar,
    #ffffff: baz,
);

a {
  name: map-get($map, purple) == foo;
  func: map-get($map, rgba(1,2,3,1)) == bar;
  hex: map-get($map, #ffffff) == baz;
}

<===> output.css
a {
  name: true;
  func: true;
  hex: true;
}