Generated by SassMeister.com.

SassMeister-input.scss

// ----
// libsass (v2.0.0)
// ----

@mixin first {
  /* first mixin was included */
  body {
    font-size: 100px;
  }
}

@mixin second {
  /* second mixin was included */
  body {
    line-height: 2;
  }
}

@mixin third {
  /* third mixin was included */
  body {
    background-color: pink;
  }
}

@mixin everything-but ($exclude: false) {
  /* The following mixins SHOULD NOT be included: #{$exclude} */
  /* first index: #{index($exclude, first)} */
  /* second index: #{index($exclude, second)} */
  /* third index: #{index($exclude, third)} */
  @if not(index($exclude, first)) {
    @include first;
  }
  @if not(index($exclude, second)) {
    @include second;
  }
  @if not(index($exclude, third)) {
    @include third;
  }
  
}

@mixin everything-specified ($include: false) {
  /* The following mixins SHOULD be included: #{$include} */
  /* first index: #{index($include, first)} */
  /* second index: #{index($include, second)} */
  /* third index: #{index($include, third)} */
  @if (index($include, first)) {
    @include first;
  }
  @if (index($include, second)) {
    @include second;
  }
  @if (index($include, third)) {
    @include third;
  }
}

/* ==================
* EVERYTHING BUT */
@include everything-but(first second);

/* ==================
* EVERYTHING SPECIFIED */
@include everything-specified(first second);

/* ==================
* IF-NOT TEST
* Does simple if-not syntax work? */

$tester: false;

@if $tester {
  p {
    font-size: 30px;
  }
  /* No, if not didn't work. */
}

@if not $tester {
  p {
    font-size: 30px;
  }
  /* Yes, if-not did work. */
}

SassMeister-output.css

/* ==================
* EVERYTHING BUT */
/* The following mixins SHOULD NOT be included: first second */
/* first index: 1 */
/* second index: 2 */
/* third index: false */
/* third mixin was included */
body {
  background-color: pink; }

/* ==================
* EVERYTHING SPECIFIED */
/* The following mixins SHOULD be included: first second */
/* first index: 1 */
/* second index: 2 */
/* third index: false */
/* first mixin was included */
body {
  font-size: 100px; }

/* second mixin was included */
body {
  line-height: 2; }

/* ==================
* IF-NOT TEST
* Does simple if-not syntax work? */
p {
  font-size: 30px; }

/* Yes, if-not did work. */