Generated by SassMeister.com.

SassMeister-input.scss

// ----
// libsass (v3.2.5)
// ----

@mixin short($map, $prefix: '') {
  @each $key, $val in $map {
    @if 'map' == type-of($val) {
      @include short($val, $prefix+$key+'-');
    }
    @else {
      #{$prefix+$key}: $val;
    }
  }
}

foo {
  @include short((
    margin: (
      left: 4px,
      top:  1em
    ),
    font: (
      family: (Arial, sans-serif),
      size: 1.6em
    )
  ));
}

SassMeister-output.css

foo {
  margin-left: 4px;
  margin-top: 1em;
  font-family: Arial, sans-serif;
  font-size: 1.6em;
}