Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.5)
// Compass (v1.0.0.alpha.18)
// ----

$mqsupport: true;
$static-bp: tablet;
$breakpoints: (
  mobile: (false, 100),
  tablet: (100, 200),
  desktop: (200, false)  
);

@function has_max($point) {
  $rtn: length(map_get($breakpoints, $point)) == 2;
  @if $rtn {
    @if nth(map_get($breakpoints, $point), 2) == false {
      $rtn: false;
    }
  }
  @return $rtn;
}

@function has_min($point) {
  $rtn: length(map_get($breakpoints, $point)) >= 1;
  @return $rtn and nth(map-get($breakpoints, $point), 1);
}

@function min($point) {
  @return nth(map_get($breakpoints, $point), 1);
}

@function max($point) {
  @return nth(map_get($breakpoints, $point), 2);
}

@mixin break($point) {
  @if $mqsupport {
    @if has_max($point) and has_min($point) {
      @media (max-width:min($point)) and (min-width:max($point)) {
        @content;
      }
    }
    @else if has_max($point) {
      @media (max-width:max($point)) {
        @content;
      }
    }
    @else if has_min($point) {
      @media (min-width:min($point)) {
        @content;
      }
    }
  }
  @else {
    @if $point == $static-bp {
      @content;
    }
  }
}

@mixin nomq() {
  @if not $mqsupport {
    @content 
  }
}

.body {
  @include break(mobile) {
    width: 50%;
  }
  @include break(tablet) {
    width: 100%;
  }
  @include break(desktop) {
    width: 10%;
  }
}

@include nomq {
  .lt-e9 {
    background: #f00;
  }
}

SassMeister-output.css

@media (max-width: 100) {
  .body {
    width: 50%;
  }
}
@media (max-width: 100) and (min-width: 200) {
  .body {
    width: 100%;
  }
}
@media (min-width: 200) {
  .body {
    width: 10%;
  }
}