sass 3.3 <3

// Use of glyphicon inside buttons

$btn-icon-space: 5px !default;

.btn {
  $icon: glyphicon; // variable for icon class name

  .#{$icon} {
    vertical-align: middle;

    @if $icon == glyphicon {
      top: -1px; // hack to center vertical
    } @else {
      top: 0;
    }

    &.#{$icon}-left {
      padding-right: $btn-icon-space;
    }
    &.#{$icon}-right {
      padding-left: $btn-icon-space;
    }
  }
}