Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.14)
// Compass (v1.0.1)
// ----

$CONSTANTS_DO_NOT_TOUCH_HAHAHA: ();

@function constant($name, $value: NULL) {
  @if ($value != NULL) {
    @if (map-has-key($CONSTANTS_DO_NOT_TOUCH_HAHAHA, $name)) {
      @warn "Constant `#{$name}` was already defined";
    }
    @else {
      $CONSTANTS_DO_NOT_TOUCH_HAHAHA: map-merge($CONSTANTS_DO_NOT_TOUCH_HAHAHA, ($name: $value));
    }
    @return map-get($CONSTANTS_DO_NOT_TOUCH_HAHAHA, $name);
  }
  @if map-has-key($CONSTANTS_DO_NOT_TOUCH_HAHAHA, $name) {
    @return map-get($CONSTANTS_DO_NOT_TOUCH_HAHAHA, $name);
  }
  @return null;
}
@mixin constant($name, $value) {
  $value: constant($name, $value);
}

@include constant("foo", "bar");
@include constant("foo", "babar");

je suis {
  au: constant(foo)
}

SassMeister-output.css

je suis {
  au: "bar";
}