SassMeister-input.scss

// ----
// Sass (v3.4.12)
// Compass (v1.0.3)
// ----

// @crazyrohila
// Global colors.
$colors: (
  dark-gray:  rgb(153, 153, 153),
  hulk:       rgb(119, 167, 109),
  teal:       #008080,
) !global;

/**
 * Helper function to get color from $colors map.
 * @params $color color to get.
 * @params $colors map of colors.
 * @return value of $color.
 */
@function color($color, $colors: $colors) {
  @if not not index("string" "color", $color) {
    @error "#{$color} value is not valid, should be string or color.";
  }
  @else if not map-has-key($colors, $color) {
    @if type-of($color) == "color" {
      @return $color;
    }
    @else {
      @error "#{$color} not found in $colors.";
    }
  }
  @return map-get($colors, $color);
}

// Demo
.main {
  background: color(hulk);
  color: color(red);
}

.footer {
  // Override global color.
  $bgs: (
    'fav': #008080,
  );
  background: color('fav', $bgs);
}

SassMeister-output.css

/**
 * Helper function to get color from $colors map.
 * @params $color color to get.
 * @params $colors map of colors.
 * @return value of $color.
 */
.main {
  background: #77a76d;
  color: red;
}

.footer {
  background: #008080;
}