class Sass::Tree::RootNode

def render
  Visitors::CheckNesting.visit(self)
  result = Visitors::Perform.visit(self)
  Visitors::CheckNesting.visit(result) # Check again to validate mixins
  result, extends = Visitors::Cssize.visit(result)
  Visitors::Extend.visit(result, extends)
  result.to_s
end