Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.0.rc.1)
// Compass (v1.0.0.alpha.20)
// ----

$zindex: (
  one: 9,
  two: 10,
);

@function zindex($z) {
  @if not map-has-key($zindex, $z) {
    @warn "No z-index found in $zindex map for `#{$z}`. Property omitted.";
  }
  @return map-get($zindex, $z);
}

.test {
  z-index: zindex(one);
}

SassMeister-output.css

.test {
  z-index: 9;
}