public static void traverse(VariableNode node) { VariableNode variable = ScssStylesheet.getVariable(node.getName()); if (!node.isGuarded() || variable == null || variable.getExpr() == null || (variable.getExpr().getLexicalUnitType() == SCSSLexicalUnit.SCSS_NULL && variable .getExpr().getNextLexicalUnit() == null)) { ScssStylesheet.addVariable(node); } node.getParentNode().removeChild(node); } }