XML - 期望属性的开放引用

Question

我正在尝试为以下xml添加dtd，但我得到Open quote is expected for attribute "play" associated with an element type "movie"

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE table [
<!ATTLIST movie play (yes | No ) >
]>
<table>
    <movie play="yes">
    </movie>
</table>

Answer 1

默认值是必需的，如：

def breadth_first_search(adj_matrix, source_index, end_index)
  node_queue = [source_index]
  puts "#{source_index} stored into queue \n"

  loop do
    curr_node = node_queue.pop
    puts "#{curr_node} popped \n"
    return false if curr_node == nil
    return true if curr_node == end_index

    children = (0..adj_matrix.length-1).to_a.select do |i| 
      adj_matrix[curr_node][i] == 1

    end

    puts "children: #{children}"
    node_queue = children + node_queue
    puts "node_queue: #{node_queue}"
  end
end

错误信息可能更好： - ）