#!/usr/bin/ruby -I.

require 'optparse'
require 'optparse/time'
require 'pp'

# keywords
CODES = %w[iso-2022-jp shift_jis euc-jp utf8 binary]
CODE_ALIASES = {"jis" => "iso-2022-jp", "sjis" => "shift_jis"}
POSSIBLE_CODES = "(#{(CODES+CODE_ALIASES.keys).join(',')})"

ARGV.options do
  |opts|
  opts.banner << " argv..."

  # separator
  opts.on_tail
  opts.on_tail("common options:")

  # no argument, shows at tail
  opts.on_tail("--help", "show this message") do
    puts opts
    exit
  end

  # mandatory argument
  opts.on("-r", "--require=LIBRARY", String,
          "require the LIBRARY, before",
          "executing your script") do
    |lib|
    @library = lib
  end

  # optional argument
  opts.on("-i", "--inplace=[EXTENSION]",
          "edit ARGV files in place", # multiline description
          "(make backup if EXTENSION supplied)") do
    |inplace|
    @inplace = inplace || ''
  end

  opts.on("-N=[NUM]", Integer) do
    |num|
    @number = num
  end

  # additional class
  opts.on("-t", "--[no-]time[=TIME]", Time, "it's the time") do
    |time|
    @time = time
  end

  # limit argument syntax
  opts.on("-[0-7]", "-F", "--irs=[OCTAL]", OptionParser::OctalInteger,
          "specify record separator", "(\\0, if no argument)") do
    |irs|
    @irs = irs
  end

  # boolean switch(default true)
  @exec = true
  opts.on("-n", "--no-exec[=FLAG]", TrueClass, "not really execute") do
    |exec|
    @exec = exec
  end

  # array
  opts.on("-a", "--list[=LIST,LIST]", Array, "list") do
    |list|
    @list = list
  end

  # fixed size array
  opts.on("--pair[=car,cdr]", Array, "pair") do
    |x, y|
    @x = x
    @y = y
  end

  # keyword completion
  opts.on("--code=CODE", CODES, CODE_ALIASES, "select coding system",
          "("+CODES.join(",")+",", " "+CODE_ALIASES.keys.join(",")+")") do
    |c|
    @code = c
  end

  # optional argument with keyword completion
  opts.on("--type[=TYPE]", [:text, :binary], "select type(text, binary)") do
    |t|
    @type = t
  end

  # boolean switch with optional argument(default false)
  opts.on("-v", "--[no-]verbose=[FLAG]", "run verbosely") do
    |v|
    @verbose = v
  end

  # easy way, set local variable
  opts.on("-q", "--quit", "quit when ARGV is empty") do
    |q|
    @quit = q
  end

  # adding on the fly
  opts.on("--add=SWITCH=[ARG]", "add option on the fly", /\A(\w+)(?:=.+)?\Z/) do
    |opt, var|
    opts.on("--#{opt}", "added in runtime", &eval("proc {|x|@#{var}=x}"))
  end

  opts.on_head("specific options:")

  # no argument
  opts.on_tail("--version", "show version") do
    puts OptionParser::Version.join('.')
    exit
  end
  opts.parse!
end

pp self
begin print ARGV.options; exit end if @quit
ARGV.options = nil		# no more parse
puts "ARGV = #{ARGV.join(' ')}" if !ARGV.empty?
#opts.variable.each {|sym| puts "#{sym} = #{opts.send(sym).inspect}"}