@ruleset: {

   color: black;
   background: white;
};

@a: 1px; .wrap-mixin(@ruleset) {

@a: hidden and if you see this in the output its a bug;
@b: visible;
@d: magic-frame; // same behaviour as mixin calls - falls back to this frame
.wrap-selector {
    @c: visible;
    @ruleset();
    visible-one: @b;
    visible-two: @c;
  }

};

.wrap-mixin({

color: black;
one: @a;
@b: hidden and if you see this in the output its a bug;
@c: hidden and if you see this in the output its a bug;
four: @d;

});

.wrap-mixin(@ruleset: {

color: red;

});

.wrap-mixin(@ruleset);

.desktop-and-old-ie(@rules) {

@media screen and (min-width: 1200) { @rules(); }
html.lt-ie9 &                       { @rules(); }

}

header {

background: blue;

.desktop-and-old-ie({
  background: red;
});

}

.wrap-mixin-calls-wrap(@ruleset) {

.wrap-mixin(@ruleset);

};

.wrap-mixin({

test: extra-wrap;
.wrap-mixin-calls-wrap({
  test: wrapped-twice;
});

});

.wrap-mixin({

test-func: unit(90px);
test-arithmetic: unit((9+9), px);

}); // without mixins @ruleset-2: {

b: 1;

}; .without-mixins {

@ruleset-2();

} @my-ruleset: {

  .my-selector {
    @media tv {
      background-color: black;
    }
  }
};

@media (orientation:portrait) {

@my-ruleset();
.wrap-media-mixin({
  @media tv {
    .triple-wrapped-mq {
      triple: true;
    }
  }
});

} .wrap-media-mixin(@ruleset) {

@media widescreen {
  @media print {
    @ruleset();
  }
  @ruleset();
}
@ruleset();

} // unlocking mixins @my-mixins: {

.mixin() {
  test: test;
}

}; @my-mixins(); .a {

.mixin();

}