class Sass::Engine

def parse_else(parent, line, text)
  previous = parent.last
  raise SyntaxError.new("@else must come after @if.") unless previous.is_a?(Tree::IfNode)
  if text
    if text !~ /^if\s+(.+)/
      raise SyntaxError.new("Invalid else directive '@else #{text}': expected 'if <expr>'.", @line)
    end
    expr = parse_script($1, :offset => line.offset + line.text.index($1))
  end
  node = Tree::IfNode.new(expr)
  append_children(node, line.children, false)
  previous.add_else node
  nil
end