Generated by SassMeister.com.

SassMeister-input.scss

// ----
// libsass (v0.7.0)
// ----

@import "bourbon/bourbon";

/*calculator*/

@mixin calc ($attr, $value, $tb-property: null, $percent: 100%, $operator: '-') {
  @if $tb-property == 0 {
    #{$attr}: 0 calc(#{$percent} #{$operator} #{$value});
  } @else if $tb-property != 0 {
    #{$attr}: calc(#{$percent} #{$operator} #{$value});
  }
}

.block {
  @include calc(width, em(50), $percent: '80%', $operator: '-');
}

.brick {
  @include calc(margin, em(30), 0);
}

SassMeister-output.css

/*calculator*/
.block {
  width: calc(80% - 3.125em); }

.brick {
  margin: 0 calc(100% - 1.875em); }