Generated by SassMeister.com.

SassMeister-input.scss

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

@mixin progress_bar($steps) {
	
	$width: (100/$steps)*1%;
	
	@for $i from 1 through $steps {
	
		[data-progress='#{$i}']:after {
			width: $width*$i;
		}
		
		$steps: $steps - 1;
	}
}
@include progress_bar(4);

SassMeister-output.css

[data-progress='1']:after {
  width: 25%;
}

[data-progress='2']:after {
  width: 50%;
}

[data-progress='3']:after {
  width: 75%;
}

[data-progress='4']:after {
  width: 100%;
}