variable interpolations in Sass

input.scss

// ----
// Sass (v3.4.21)
// Compass (v1.0.3)
// ----

$color-rebeccapurple: rebeccapurple; 
$color-red: red;
$color-blue: blue;

@mixin color(
  $color: $color-red,
  $color-hover: $color
) {
  color: $color;
  &:hover {
    color: $color-hover;
  }
}

b {
}


a {
  @include color;
  
  &.blue {
    @include color($color: $color-blue);
  }
  
  &.different-hover {
    @include color($color: $color-blue, $color-hover: $color-rebeccapurple);
  }
}

output.css

a {
  color: red;
}
a:hover {
  color: red;
}
a.blue {
  color: blue;
}
a.blue:hover {
  color: blue;
}
a.different-hover {
  color: blue;
}
a.different-hover:hover {
  color: rebeccapurple;
}

SassMeister-input.scss

// ----
// Sass (v3.4.21)
// Compass (v1.0.3)
// ----

$color-rebeccapurple: rebeccapurple; 
$color-red: red;
$color-blue: blue;

@mixin color(
  $color: $color-red,
  $color-hover: $color
) {
  color: $color;
  &:hover {
    color: $color-hover;
  }
}

b {
}


a {
  @include color;
  
  &.blue {
    @include color($color: $color-blue);
  }
  
  &.different-hover {
    @include color($color: $color-blue, $color-hover: $color-rebeccapurple);
  }
}

SassMeister-output.css

a {
  color: red;
}
a:hover {
  color: red;
}
a.blue {
  color: blue;
}
a.blue:hover {
  color: blue;
}
a.different-hover {
  color: blue;
}
a.different-hover:hover {
  color: rebeccapurple;
}