Generate Relax Ng template from HTML

relax.rb

require 'nokogiri'
require 'open-uri'

unless [1,2].include? ARGV.length
  puts "Usage: arrest template-url [css-selector]"
  exit 1
end

def relax node, indent = 0
  tab  = '  '
  pad  = tab * indent
  if ignore node
    (node.children.map do |c|
      relax(c, indent)
    end.select {|k| k != ''}).join(",\n")
  else
    if node.name == 'text'
      result = "#{pad}\"#{node.text().strip}\""
    else
      result = "#{pad}element #{node.name} {\n"
      kids = []
      kids += node.attributes.map do |a|
        "#{tab}#{pad}attribute #{a[0]} { \"#{a[1].text().strip}\" }"
      end.select { |k| k != '' }
      kids += node.children.map do |c|
        relax(c, indent+1)
      end.select { |k| k != '' }
      result << kids.join(",\n")
      result << "\n" unless kids.empty?
      result << "#{pad}}"
    end
  end
end

def ignore node
  %w{html document comment script meta #cdata-section}.include? node.name or
    (node.name == 'text' and node.text().strip.empty?)
end

doc = Nokogiri::HTML(open(ARGV[0]))
doc = doc.css(ARGV[1]).first if ARGV[1]

puts(relax doc)