递归/嵌套收益率答案

【问题标题】：Recursive/nested yield递归/嵌套收益率
【发布时间】：2015-04-29 17:22:43
【问题描述】：

我有以下几种使用 Nokogiri 编辑深度嵌套的 XML 结构的方法。我想在深入研究结构时删除一些样板，所以我想重构这些方法。

这里是方法

def create_acl(acl_name, addresses)
  connection.rpc.edit_config do |x|
    # `x` is a `Nokogiri::XML::Builder` object.
    x.configuration do
      x.firewall do
        x.family do
          x.inet do
            x.filter do
              x.name(acl_name)
              add_acl_whitelist(x, addresses)
              add_acl_blacklist(x)
            end
          end
        end
      end
    end
  end
end

def link_options
  connection.rpc.edit_config do |x|
    # `x` is a `Nokogiri::XML::Builder` object.
    x.configuration do
      x.interfaces do
        x.interface do
          x.name(interface['interface'])
          x.send(:'ether-options') do
            x.send(:'802.3ad') do
              additional.each_pair { |attr, value| x.send(attr) { x.send(value) } }
            end
          end
        end
      end
    end
  end
end

我想我想把它们重构成这样：

def create_acl(acl_name, addresses)
  edit_config(:firewall, :family, :inet, :filter) do |x|
    x.name(acl_name)
    add_acl_whitelist(x, addresses)
    add_acl_blacklist(x)
  end
end

def link_options
  edit_config(:interfaces, :interface) do |x|
    x.name(interface['interface'])
    x.send(:'ether-options') do
      x.send(:'802.3ad') do
        additional.each_pair { |attr, value| x.send(attr) { x.send(value) } }
      end
    end
  end
end

def edit_config(*parents, &block)
  connection.rpc.edit_config do |x|
    # Recursively yield each item in `parents` to x, then yield the given
    # block...
    #
    # Something like this, only with yielding?
    #
    # parents = parents.unshift(:configuration)
    # parents.each { |method| x.send(method, &block) }
  end
end

关于如何嵌套可以传递给该方法的可变数量的产量有什么想法吗？如果没有，关于如何在这些方法中重构样板文件有什么其他想法吗？

提前致谢！

【问题讨论】：

标签： ruby recursion nokogiri yield

【解决方案1】：

看看这种风格是否有帮助：

puts "Usual nested way : "
3.times do |x|
    x.times do
        x.times do 
            puts x
        end
    end
end
# => 
# 1
# 2
# 2
# 2
# 2

puts "Using recursion : "
def compact_nested_blocks(*funcs, &leaf_block)
    3.times do |x| # Place the call to your parent block (connection.rpc ...).
        sub_block(x, *funcs, &leaf_block)
    end
end

def sub_block(obj, *funcs, &leaf_block) 
    obj.send(funcs.shift) do
        funcs.empty?? yield(obj) : sub_block(obj, *funcs, &leaf_block)
    end
end

# Call it with your methods instead of 'times'.
compact_nested_blocks(:times, :times) do |x|
    puts x
end
# => 
# 1
# 2
# 2
# 2
# 2

我无法在本地使用您的代码对其进行测试。更换您需要的核心线，看看是否足够。

【讨论】：