Parse Command Line Arguments in ruby

gistfile1.rb

if $0 == __FILE__
  ARGV.each{|arg|
    case arg
    when /\A--ruby=(.+)/
      $ruby_program = $1
    when /\A--matzruby=(.+)/
      $matzruby_program = $1
    when /\A--opts=(.+)/
      $opts = $1
    when /\A(-r|--only-ruby)\z/
      $rubyonly = true
    when /\A(-m|--only-matzruby)\z/
      $matzrubyonly = true
    end
  }
  ARGV.delete_if{|arg|
    /\A-/ =~ arg
  }
end