code: private String createExpressionKey(String suffix) {
  		String[] parts = suffix.split("_");
  		StringBuilder ret = new StringBuilder("[if ");
  		boolean ieAdded = false;
  		for (String part : parts) {
  			if ("".equals(part)) {
  				continue;
  			}
  			if ("ie".equals(part)) {
  				break;
  			} else if (Pattern.matches("(lt|lte|gt|gte)", part)) {
  				ret.append(part).append(" ");
  			} else {
  				ret.append("IE ").append(part);
  				ieAdded = true;
  			}
  		}
  		if (!ieAdded)
  			ret.append("IE");
  		ret.append("]");
  		return ret.toString();
  	}
docs: Creates an IE conditional expression by transforming the suffix of a
  filename.
  
  @param suffix
  @return