print arranged Xml

xmlprinter.rb

#! /usr/bin/env ruby
# -*- coding: utf-8 -*-

require 'optparse'

Version = "0.1.0"
$arg_options = Hash.new
$arg_options[:t] = false
$opts = OptionParser.new {|opt|
  begin
    opt.banner = "usage: #{opt.program_name} xmlfile"
    opt.on('-t', '--text', 'text-only extract mode') {|v| $arg_options[:t] = true}
    opt.parse!(ARGV)
  rescue OptionParser::ParseError => e
    $stderr.print  e
    $stderr.puts opt.banner
    exit
  end
}

class XmlPrinterException < Exception; end

class XmlPrinter
  def initialize(data)
    @xml_data = data
    @result = ""
  end

  def print()
    depth = 0
    @xml_data.scan(/<.*?>|<\/.*?>|<.*?\/>|.*?(?=<)/).each do |line|
      line.strip!
      if normaltag?(line) then 
        if starttag?(line) then
          add_string(line, depth)
          depth += 1
        elsif endtag?(line) then 
          depth -= 1
          add_string(line, depth)
        elsif emptytag?(line) then
          add_string(line, depth)
        else
          $stderr.puts line
          raise XmlPrinterException.new, 'xml format error'
        end
      else  # tag includeing text
        depth += 1
        add_string(line, depth)
        depth -= 1
        if $arg_options[:t] then
          @result += line
        end
      end
    end

    return @result
  end

  private
  def add_string(line, depth)
    if $arg_options[:t] == false then
      @result += "  " * depth + line + "\n"
    end
  end

  def normaltag?(line)
    return (line[0] == '<' && line[-1] == '>')
  end

  def starttag?(line)
    return (line[1] != '/' && line[-2] != '/')
  end

  def endtag?(line)
    return (line[1] == '/' && line[-2] != '/')
  end

  def emptytag?(line)
    return (line[1] != '/' && line[-2] == '/')
  end
end

def print_xmlfile(xmlfile)
  if File.file?(xmlfile) == false then
    if File.directory?(xmlfile) then
      $stderr.print "#{xmlfile} is directory"
    else 
      $stderr.print "#{xmlfile} : no such file or directory"
    end
    $stderr.print $opts.help
    exit
  end

  xml_data = ""
  File.open(xmlfile) {|f|
    xml_data = f.read
  }

  begin
    printer = XmlPrinter.new(xml_data)
    printed_data = printer.print
    print printed_data
  rescue XmlPrinterException => e
    p e
    exit
  end
end

def main()
  if ARGV.size == 0 then
    $stderr.print "too few arguments"
    $stderr.print $opts.help
    exit
  end

  ARGV.each do |arg|
    print_xmlfile(arg)
  end

  exit
end

if __FILE__ == $0 then
  main()
end