有没有办法用垂直对齐方式打印XML？

<Presidents>
  <President first="George" last="Washington" number="1" year="1789" />
  <President first="John" last="Adams" number="2" year="1797" />
</Presidents>

我想有一个漂亮的打印机垂直对齐我的属性,所以文件看起来像：

<Presidents>
  <President first="George" last="Washington" number="1" year="1789" />
  <President first="John"   last="Adams"      number="2" year="1797" />
</Presidents>

这种格式化样式取决于具有相同属性的元素列表,因此它可能无法一般地应用于任何xml文档,但是,它是配置文件的常见样式.我已经阅读了xmllint和xmlstarlet的手册页,我找不到任何像这样的功能的引用.

#!/usr/bin/env ruby
#
# vertically aligns columns

def print_buf(b)
  max_lengths={}
  max_lengths.default=0

  b.each do |line|
    for i in (0..line.size() - 1)
      d = line[i]
      s = d.size()
      if s > max_lengths[i] then
        max_lengths[i] = s
      end
    end
  end

  b.each do |line|
    for i in (0..line.size() - 1)
      print line[i], ' ' * (max_lengths[i] - line[i].size())
    end
  end

end

cols=0
buf=[]

ARGF.each do |line|
  columns=line.split(/( |\r\n|\n|\r)(?=(?:[^\"]*\"[^\"]*\")*(?![^\"]*\"))/m)
  if columns.size != cols then
    print_buf(buf) if !buf.empty?
    buf=[]
  end
  buf << columns
  cols = columns.size
end

print_buf(buf)