Commits

Chad Perrin committed 9df43d2 Draft

trollop is a dependency now

Comments (3)

  1. seydar

    Actually, this is a modified file. I had modified Trollop::options to take an argument (which defaulted to ARGV, see line 663) so that we could use trollop to parse a subset of ARGV and have it be used for subcommands. You might find that running subcommands will not work as they should.

  2. seydar

    Also, trollop is a library instead of a dependency because eliminating the need for rubygems made startup time MUCH faster. It allowed us to reach Mercurial speeds and be a real competitor.

Files changed (1)

lib/amp/dependencies/trollop.rb

-## lib/trollop.rb -- trollop command-line processing library
-## Author::    William Morgan (mailto: wmorgan-trollop@masanjin.net)
-## Copyright:: Copyright 2007 William Morgan
-## License::   GNU GPL version 2
-
-module Trollop
-  
-  VERSION = "1.13"
-  
-  ## Thrown by Parser in the event of a commandline error. Not needed if
-  ## you're using the Trollop::options entry.
-  class CommandlineError < StandardError; end
-    
-  ## Thrown by Parser if the user passes in '-h' or '--help'. Handled
-  ## automatically by Trollop#options.
-  class HelpNeeded < StandardError; end
-  
-  ## Thrown by Parser if the user passes in '-h' or '--version'. Handled
-  ## automatically by Trollop#options.
-  class VersionNeeded < StandardError; end
-  
-  ## Regex for floating point numbers
-  FLOAT_RE = /^-?((\d+(\.\d+)?)|(\.\d+))$/
-  
-  ## Regex for parameters
-  PARAM_RE = /^-(-|\.$|[^\d\.])/
-  
-  ## The commandline parser. In typical usage, the methods in this class
-  ## will be handled internally by Trollop::options. In this case, only the
-  ## #opt, #banner and #version, #depends, and #conflicts methods will
-  ## typically be called.
-  ##
-  ## If it's necessary to instantiate this class (for more complicated
-  ## argument-parsing situations), be sure to call #parse to actually
-  ## produce the output hash.
-  class Parser
-  
-    ## The set of values that indicate a flag option when passed as the
-    ## +:type+ parameter of #opt.
-    FLAG_TYPES = [:flag, :bool, :boolean]
-  
-    ## The set of values that indicate a single-parameter option when
-    ## passed as the +:type+ parameter of #opt.
-    ##
-    ## A value of +io+ corresponds to a readable IO resource, including
-    ## a filename, URI, or the strings 'stdin' or '-'.
-    SINGLE_ARG_TYPES = [:int, :integer, :string, :double, :float, :io]
-  
-    ## The set of values that indicate a multiple-parameter option when
-    ## passed as the +:type+ parameter of #opt.
-    MULTI_ARG_TYPES = [:ints, :integers, :strings, :doubles, :floats, :ios]
-  
-    ## The complete set of legal values for the +:type+ parameter of #opt.
-    TYPES = FLAG_TYPES + SINGLE_ARG_TYPES + MULTI_ARG_TYPES
-  
-    INVALID_SHORT_ARG_REGEX = /[\d-]/ #:nodoc:
-  
-    ## The values from the commandline that were not interpreted by #parse.
-    attr_reader :leftovers
-  
-    ## The complete configuration hashes for each option. (Mainly useful
-    ## for testing.)
-    attr_reader :specs
-  
-    ## Initializes the parser, and instance-evaluates any block given.
-    def initialize *a, &b
-      @version = nil
-      @leftovers = []
-      @specs = {}
-      @long = {}
-      @short = {}
-      @order = []
-      @constraints = []
-      @stop_words = []
-      @stop_on_unknown = false
-  
-      #instance_eval(&b) if b # can't take arguments
-      cloaker(&b).bind(self).call(*a) if b
-    end
-  
-    ## Define an option. +name+ is the option name, a unique identifier
-    ## for the option that you will use internally, which should be a
-    ## symbol or a string. +desc+ is a string description which will be
-    ## displayed in help messages.
-    ##
-    ## Takes the following optional arguments:
-    ##
-    ## [+:long+] Specify the long form of the argument, i.e. the form with two dashes. If unspecified, will be automatically derived based on the argument name by turning the +name+ option into a string, and replacing any _'s by -'s.
-    ## [+:short+] Specify the short form of the argument, i.e. the form with one dash. If unspecified, will be automatically derived from +name+.
-    ## [+:type+] Require that the argument take a parameter or parameters of type +type+. For a single parameter, the value can be a member of +SINGLE_ARG_TYPES+, or a corresponding Ruby class (e.g. +Integer+ for +:int+). For multiple-argument parameters, the value can be any member of +MULTI_ARG_TYPES+ constant. If unset, the default argument type is +:flag+, meaning that the argument does not take a parameter. The specification of +:type+ is not necessary if a +:default+ is given.
-    ## [+:default+] Set the default value for an argument. Without a default value, the hash returned by #parse (and thus Trollop::options) will have a +nil+ value for this key unless the argument is given on the commandline. The argument type is derived automatically from the class of the default value given, so specifying a +:type+ is not necessary if a +:default+ is given. (But see below for an important caveat when +:multi+: is specified too.) If the argument is a flag, and the default is set to +true+, then if it is specified on the the commandline the value will be +false+.
-    ## [+:required+] If set to +true+, the argument must be provided on the commandline.
-    ## [+:multi+] If set to +true+, allows multiple occurrences of the option on the commandline. Otherwise, only a single instance of the option is allowed. (Note that this is different from taking multiple parameters. See below.)
-    ##
-    ## Note that there are two types of argument multiplicity: an argument
-    ## can take multiple values, e.g. "--arg 1 2 3". An argument can also
-    ## be allowed to occur multiple times, e.g. "--arg 1 --arg 2".
-    ##
-    ## Arguments that take multiple values should have a +:type+ parameter
-    ## drawn from +MULTI_ARG_TYPES+ (e.g. +:strings+), or a +:default:+
-    ## value of an array of the correct type (e.g. [String]). The
-    ## value of this argument will be an array of the parameters on the
-    ## commandline.
-    ##
-    ## Arguments that can occur multiple times should be marked with
-    ## +:multi+ => +true+. The value of this argument will also be an array.
-    ##
-    ## These two attributes can be combined (e.g. +:type+ => +:strings+,
-    ## +:multi+ => +true+), in which case the value of the argument will be
-    ## an array of arrays.
-    ##
-    ## There's one ambiguous case to be aware of: when +:multi+: is true and a
-    ## +:default+ is set to an array (of something), it's ambiguous whether this
-    ## is a multi-value argument as well as a multi-occurrence argument.
-    ## In thise case, Trollop assumes that it's not a multi-value argument.
-    ## If you want a multi-value, multi-occurrence argument with a default
-    ## value, you must specify +:type+ as well.
-  
-    def opt name, desc="", opts={}
-      raise ArgumentError, "you already have an argument named '#{name}'" if @specs.member? name
-  
-      ## fill in :type
-      opts[:type] = # normalize
-        case opts[:type]
-        when :boolean, :bool; :flag
-        when :integer; :int
-        when :integers; :ints
-        when :double; :float
-        when :doubles; :floats
-        when Class
-          case opts[:type].to_s # sigh... there must be a better way to do this
-          when 'TrueClass', 'FalseClass'; :flag
-          when 'String'; :string
-          when 'Integer'; :int
-          when 'Float'; :float
-          when 'IO'; :io
-          else
-            raise ArgumentError, "unsupported argument type '#{opts[:type].class.name}'"
-          end
-        when nil; nil
-        else
-          raise ArgumentError, "unsupported argument type '#{opts[:type]}'" unless TYPES.include?(opts[:type])
-          opts[:type]
-        end
-  
-      ## for options with :multi => true, an array default doesn't imply
-      ## a multi-valued argument. for that you have to specify a :type
-      ## as well. (this is how we disambiguate an ambiguous situation;
-      ## see the docs for Parser#opt for details.)
-      disambiguated_default =
-        if opts[:multi] && opts[:default].is_a?(Array) && !opts[:type]
-          opts[:default].first
-        else
-          opts[:default]
-        end
-  
-      type_from_default =
-        case disambiguated_default
-        when Integer; :int
-        when Numeric; :float
-        when TrueClass, FalseClass; :flag
-        when String; :string
-        when IO; :io
-        when Array
-          if opts[:default].empty?
-            raise ArgumentError, "multiple argument type cannot be deduced from an empty array for '#{opts[:default][0].class.name}'"
-          end
-          case opts[:default][0]    # the first element determines the types
-          when Integer; :ints
-          when Numeric; :floats
-          when String; :strings
-          when IO; :ios
-          else
-            raise ArgumentError, "unsupported multiple argument type '#{opts[:default][0].class.name}'"
-          end
-        when nil; nil
-        else
-          raise ArgumentError, "unsupported argument type '#{opts[:default].class.name}'"
-        end
-  
-      raise ArgumentError, ":type specification and default type don't match" if opts[:type] && type_from_default && opts[:type] != type_from_default
-  
-      opts[:type] = opts[:type] || type_from_default || :flag
-  
-      ## fill in :long
-      opts[:long] = opts[:long] ? opts[:long].to_s : name.to_s.gsub("_", "-")
-      opts[:long] =
-        case opts[:long]
-        when /^--([^-].*)$/
-          $1
-        when /^[^-]/
-          opts[:long]
-        else
-          raise ArgumentError, "invalid long option name #{opts[:long].inspect}"
-        end
-      raise ArgumentError, "long option name #{opts[:long].inspect} is already taken; please specify a (different) :long" if @long[opts[:long]]
-  
-      ## fill in :short
-      opts[:short] = opts[:short].to_s if opts[:short] unless opts[:short] == :none
-      opts[:short] = case opts[:short]
-        when /^-(.)$/; $1
-        when nil, :none, /^.$/; opts[:short]
-        else raise ArgumentError, "invalid short option name '#{opts[:short].inspect}'"
-      end
-  
-      if opts[:short]
-        raise ArgumentError, "short option name #{opts[:short].inspect} is already taken; please specify a (different) :short" if @short[opts[:short]]
-        raise ArgumentError, "a short option name can't be a number or a dash" if opts[:short] =~ INVALID_SHORT_ARG_REGEX
-      end
-  
-      ## fill in :default for flags
-      opts[:default] = false if opts[:type] == :flag && opts[:default].nil?
-  
-      ## autobox :default for :multi (multi-occurrence) arguments
-      opts[:default] = [opts[:default]] if opts[:default] && opts[:multi] && !opts[:default].is_a?(Array)
-  
-      ## fill in :multi
-      opts[:multi] ||= false
-  
-      opts[:desc] ||= desc
-      @long[opts[:long]] = name
-      @short[opts[:short]] = name if opts[:short] && opts[:short] != :none
-      @specs[name] = opts
-      @order << [:opt, name]
-    end
-  
-    ## Sets the version string. If set, the user can request the version
-    ## on the commandline. Should probably be of the form "<program name>
-    ## <version number>".
-    def version s=nil; @version = s if s; @version end
-  
-    ## Adds text to the help display. Can be interspersed with calls to
-    ## #opt to build a multi-section help page.
-    def banner s; @order << [:text, s] end
-    alias :text :banner
-  
-    ## Marks two (or more!) options as requiring each other. Only handles
-    ## undirected (i.e., mutual) dependencies. Directed dependencies are
-    ## better modeled with Trollop::die.
-    def depends *syms
-      syms.each { |sym| raise ArgumentError, "unknown option '#{sym}'" unless @specs[sym] }
-      @constraints << [:depends, syms]
-    end
-    
-    ## Marks two (or more!) options as conflicting.
-    def conflicts *syms
-      syms.each { |sym| raise ArgumentError, "unknown option '#{sym}'" unless @specs[sym] }
-      @constraints << [:conflicts, syms]
-    end
-  
-    ## Defines a set of words which cause parsing to terminate when
-    ## encountered, such that any options to the left of the word are
-    ## parsed as usual, and options to the right of the word are left
-    ## intact.
-    ##
-    ## A typical use case would be for subcommand support, where these
-    ## would be set to the list of subcommands. A subsequent Trollop
-    ## invocation would then be used to parse subcommand options, after
-    ## shifting the subcommand off of ARGV.
-    def stop_on *words
-      @stop_words = [*words].flatten
-    end
-  
-    ## Similar to #stop_on, but stops on any unknown word when encountered
-    ## (unless it is a parameter for an argument). This is useful for
-    ## cases where you don't know the set of subcommands ahead of time,
-    ## i.e., without first parsing the global options.
-    def stop_on_unknown
-      @stop_on_unknown = true
-    end
-  
-    ## Parses the commandline. Typically called by Trollop::options.
-    def parse cmdline=ARGV
-      vals = {}
-      required = {}
-  
-      opt :version, "Print version and exit" if @version unless @specs[:version] || @long["version"]
-      opt :help, "Show this message" unless @specs[:help] || @long["help"]
-  
-      @specs.each do |sym, opts|
-        required[sym] = true if opts[:required]
-        vals[sym] = opts[:default]
-      end
-  
-      resolve_default_short_options
-  
-      ## resolve symbols
-      given_args = {}
-      @leftovers = each_arg cmdline do |arg, params|
-        sym = case arg
-        when /^-([^-])$/
-          @short[$1]
-        when /^--([^-]\S*)$/
-          @long[$1]
-        else
-          raise CommandlineError, "invalid argument syntax: '#{arg}'"
-        end
-        raise CommandlineError, "unknown argument '#{arg}'" unless sym
-  
-        if given_args.include?(sym) && !@specs[sym][:multi]
-          raise CommandlineError, "option '#{arg}' specified multiple times"
-        end
-  
-        given_args[sym] ||= {}
-  
-        given_args[sym][:arg] = arg
-        given_args[sym][:params] ||= []
-  
-        # The block returns the number of parameters taken.
-        num_params_taken = 0
-  
-        unless params.nil?
-          if SINGLE_ARG_TYPES.include?(@specs[sym][:type])
-            given_args[sym][:params] << params[0, 1]  # take the first parameter
-            num_params_taken = 1
-          elsif MULTI_ARG_TYPES.include?(@specs[sym][:type])
-            given_args[sym][:params] << params        # take all the parameters
-            num_params_taken = params.size
-          end
-        end
-  
-        num_params_taken
-      end
-  
-      ## check for version and help args
-      raise VersionNeeded if given_args.include? :version
-      raise HelpNeeded if given_args.include? :help
-  
-      ## check constraint satisfaction
-      @constraints.each do |type, syms|
-        constraint_sym = syms.find { |sym| given_args[sym] }
-        next unless constraint_sym
-  
-        case type
-        when :depends
-          syms.each { |sym| raise CommandlineError, "--#{@specs[constraint_sym][:long]} requires --#{@specs[sym][:long]}" unless given_args.include? sym }
-        when :conflicts
-          syms.each { |sym| raise CommandlineError, "--#{@specs[constraint_sym][:long]} conflicts with --#{@specs[sym][:long]}" if given_args.include?(sym) && (sym != constraint_sym) }
-        end
-      end
-  
-      required.each do |sym, val|
-        raise CommandlineError, "option '#{sym}' must be specified" unless given_args.include? sym
-      end
-  
-      ## parse parameters
-      given_args.each do |sym, given_data|
-        arg = given_data[:arg]
-        params = given_data[:params]
-  
-        opts = @specs[sym]
-        raise CommandlineError, "option '#{arg}' needs a parameter" if params.empty? && opts[:type] != :flag
-  
-        vals["#{sym}_given".intern] = true # mark argument as specified on the commandline
-  
-        case opts[:type]
-        when :flag
-          vals[sym] = !opts[:default]
-        when :int, :ints
-          vals[sym] = params.map { |pg| pg.map { |p| parse_integer_parameter p, arg } }
-        when :float, :floats
-          vals[sym] = params.map { |pg| pg.map { |p| parse_float_parameter p, arg } }
-        when :string, :strings
-          vals[sym] = params.map { |pg| pg.map { |p| p.to_s } }
-        when :io, :ios
-          vals[sym] = params.map { |pg| pg.map { |p| parse_io_parameter p, arg } }
-        end
-  
-        if SINGLE_ARG_TYPES.include?(opts[:type])
-          unless opts[:multi]       # single parameter
-            vals[sym] = vals[sym][0][0]
-          else                      # multiple options, each with a single parameter
-            vals[sym] = vals[sym].map { |p| p[0] }
-          end
-        elsif MULTI_ARG_TYPES.include?(opts[:type]) && !opts[:multi]
-          vals[sym] = vals[sym][0]  # single option, with multiple parameters
-        end
-        # else: multiple options, with multiple parameters
-      end
-  
-      ## allow openstruct-style accessors
-      class << vals
-        def method_missing(m, *args)
-          self[m] || self[m.to_s]
-        end
-      end
-      vals
-    end
-  
-    ## Print the help message to +stream+.
-    def educate stream=$stdout
-      width # just calculate it now; otherwise we have to be careful not to
-            # call this unless the cursor's at the beginning of a line.
-  
-      left = {}
-      @specs.each do |name, spec| 
-        left[name] = "--#{spec[:long]}" +
-          (spec[:short] && spec[:short] != :none ? ", -#{spec[:short]}" : "") +
-          case spec[:type]
-          when :flag; ""
-          when :int; " <i>"
-          when :ints; " <i+>"
-          when :string; " <s>"
-          when :strings; " <s+>"
-          when :float; " <f>"
-          when :floats; " <f+>"
-          when :io; " <filename/uri>"
-          when :ios; " <filename/uri+>"
-          end
-      end
-  
-      leftcol_width = left.values.map { |s| s.length }.max || 0
-      rightcol_start = leftcol_width + 6 # spaces
-  
-      unless @order.size > 0 && @order.first.first == :text
-        stream.puts "#@version\n" if @version
-        stream.puts "Options:"
-      end
-  
-      @order.each do |what, opt|
-        if what == :text
-          stream.puts wrap(opt)
-          next
-        end
-  
-        spec = @specs[opt]
-        stream.printf "  %#{leftcol_width}s:   ", left[opt]
-        desc = spec[:desc] + begin
-          default_s = case spec[:default]
-          when $stdout; "<stdout>"
-          when $stdin; "<stdin>"
-          when $stderr; "<stderr>"
-          when Array
-            spec[:default].join(", ")
-          else
-            spec[:default].to_s
-          end
-  
-          if spec[:default]
-            if spec[:desc] =~ /\.$/
-              " (Default: #{default_s})"
-            else
-              " (default: #{default_s})"
-            end
-          else
-            ""
-          end
-        end
-        stream.puts wrap(desc, :width => width - rightcol_start - 1, :prefix => rightcol_start)
-      end
-    end
-  
-    def width #:nodoc:
-      @width ||= if $stdout.tty?
-        begin
-          require 'curses'
-          Curses::init_screen
-          x = Curses::cols
-          Curses::close_screen
-          x
-        rescue Exception
-          80
-        end
-      else
-        80
-      end
-    end
-  
-    def wrap str, opts={} # :nodoc:
-      if str == ""
-        [""]
-      else
-        str.split("\n").map { |s| wrap_line s, opts }.flatten
-      end
-    end
-  
-  private
-  
-    ## yield successive arg, parameter pairs
-    def each_arg args
-      remains = []
-      i = 0
-  
-      until i >= args.length
-        if @stop_words.member? args[i]
-          remains += args[i .. -1]
-          return remains
-        end
-        case args[i]
-        when /^--$/ # arg terminator
-          remains += args[(i + 1) .. -1]
-          return remains
-        when /^--(\S+?)=(.*)$/ # long argument with equals
-          yield "--#{$1}", [$2]
-          i += 1
-        when /^--(\S+)$/ # long argument
-          params = collect_argument_parameters(args, i + 1)
-          unless params.empty?
-            num_params_taken = yield args[i], params
-            unless num_params_taken
-              if @stop_on_unknown
-                remains += args[i + 1 .. -1]
-                return remains
-              else
-                remains += params
-              end
-            end
-            i += 1 + num_params_taken
-          else # long argument no parameter
-            yield args[i], nil
-            i += 1
-          end
-        when /^-(\S+)$/ # one or more short arguments
-          shortargs = $1.split(//)
-          shortargs.each_with_index do |a, j|
-            if j == (shortargs.length - 1)
-              params = collect_argument_parameters(args, i + 1)
-              unless params.empty?
-                num_params_taken = yield "-#{a}", params
-                unless num_params_taken
-                  if @stop_on_unknown
-                    remains += args[i + 1 .. -1]
-                    return remains
-                  else
-                    remains += params
-                  end
-                end
-                i += 1 + num_params_taken
-              else # argument no parameter
-                yield "-#{a}", nil
-                i += 1
-              end
-            else
-              yield "-#{a}", nil
-            end
-          end
-        else
-          if @stop_on_unknown
-            remains += args[i .. -1]
-            return remains
-          else
-            remains << args[i]
-            i += 1
-          end
-        end
-      end
-  
-      remains
-    end
-  
-    def parse_integer_parameter param, arg
-      raise CommandlineError, "option '#{arg}' needs an integer" unless param =~ /^\d+$/
-      param.to_i
-    end
-  
-    def parse_float_parameter param, arg
-      raise CommandlineError, "option '#{arg}' needs a floating-point number" unless param =~ FLOAT_RE
-      param.to_f
-    end
-  
-    def parse_io_parameter param, arg
-      case param
-      when /^(stdin|-)$/i; $stdin
-      else
-        require 'open-uri'
-        begin
-          open param
-        rescue SystemCallError => e
-          raise CommandlineError, "file or url for option '#{arg}' cannot be opened: #{e.message}"
-        end
-      end
-    end
-  
-    def collect_argument_parameters args, start_at
-      params = []
-      pos = start_at
-      while args[pos] && args[pos] !~ PARAM_RE && !@stop_words.member?(args[pos]) do
-        params << args[pos]
-        pos += 1
-      end
-      params
-    end
-  
-    def resolve_default_short_options
-      @order.each do |type, name|
-        next unless type == :opt
-        opts = @specs[name]
-        next if opts[:short]
-  
-        c = opts[:long].split(//).find { |c| c !~ INVALID_SHORT_ARG_REGEX && !@short.member?(c) }
-        raise ArgumentError, "can't generate a default short option name for #{opts[:long].inspect}: out of unique characters" unless c
-  
-        opts[:short] = c
-        @short[c] = name
-      end
-    end
-  
-    def wrap_line str, opts={}
-      prefix = opts[:prefix] || 0
-      width = opts[:width] || (self.width - 1)
-      start = 0
-      ret = []
-      until start > str.length
-        nextt = 
-          if start + width >= str.length
-            str.length
-          else
-            x = str.rindex(/\s/, start + width)
-            x = str.index(/\s/, start) if x && x < start
-            x || str.length
-          end
-        ret << (ret.empty? ? "" : " " * prefix) + str[start ... nextt]
-        start = nextt + 1
-      end
-      ret
-    end
-  
-    ## instance_eval but with ability to handle block arguments
-    ## thanks to why: http://redhanded.hobix.com/inspect/aBlockCostume.html
-    def cloaker &b
-      (class << self; self; end).class_eval do
-        define_method :cloaker_, &b
-        meth = instance_method :cloaker_
-        remove_method :cloaker_
-        meth
-      end
-    end
-  end
-  
-  ## The top-level entry method into Trollop. Creates a Parser object,
-  ## passes the block to it, then parses +args+ with it, handling any
-  ## errors or requests for help or version information appropriately (and
-  ## then exiting). Modifies +args+ in place. Returns a hash of option
-  ## values.
-  ##
-  ## The block passed in should contain zero or more calls to +opt+
-  ## (Parser#opt), zero or more calls to +text+ (Parser#text), and
-  ## probably a call to +version+ (Parser#version).
-  ##
-  ## The returned block contains a value for every option specified with
-  ## +opt+.  The value will be the value given on the commandline, or the
-  ## default value if the option was not specified on the commandline. For
-  ## every option specified on the commandline, a key "<option
-  ## name>_given" will also be set in the hash.
-  ##
-  ## Example:
-  ##
-  ##   require 'trollop'
-  ##   opts = Trollop::options do
-  ##     opt :monkey, "Use monkey mode"                     # a flag --monkey, defaulting to false
-  ##     opt :goat, "Use goat mode", :default => true       # a flag --goat, defaulting to true
-  ##     opt :num_limbs, "Number of limbs", :default => 4   # an integer --num-limbs <i>, defaulting to 4
-  ##     opt :num_thumbs, "Number of thumbs", :type => :int # an integer --num-thumbs <i>, defaulting to nil
-  ##   end
-  ##
-  ##   ## if called with no arguments
-  ##   p opts # => { :monkey => false, :goat => true, :num_limbs => 4, :num_thumbs => nil }
-  ##
-  ##   ## if called with --monkey
-  ##   p opts # => {:monkey_given=>true, :monkey=>true, :goat=>true, :num_limbs=>4, :help=>false, :num_thumbs=>nil}
-  ##
-  ## See more examples at http://trollop.rubyforge.org.
-  def options args = ARGV, *a, &b
-    @p = Parser.new(*a, &b)
-    begin
-      vals = @p.parse args
-      args.clear
-      @p.leftovers.each { |l| args << l }
-      [vals, @p]
-    rescue CommandlineError => e
-      $stderr.puts "Error: #{e.message}."
-      $stderr.puts "Try --help for help."
-      exit(-1)
-    rescue HelpNeeded
-      @p.educate
-      exit
-    rescue VersionNeeded
-      puts @p.version
-      exit
-    end
-  end
-  
-  ## Informs the user that their usage of 'arg' was wrong, as detailed by
-  ## 'msg', and dies. Example:
-  ##
-  ##   options do
-  ##     opt :volume, :default => 0.0
-  ##   end
-  ##
-  ##   die :volume, "too loud" if opts[:volume] > 10.0
-  ##   die :volume, "too soft" if opts[:volume] < 0.1
-  ##
-  ## In the one-argument case, simply print that message, a notice
-  ## about -h, and die. Example:
-  ##
-  ##   options do
-  ##     opt :whatever # ...
-  ##   end
-  ##
-  ##   Trollop::die "need at least one filename" if ARGV.empty?
-  def die arg, msg=nil
-    if msg
-      $stderr.puts "Error: argument --#{@p.specs[arg][:long]} #{msg}."
-    else
-      $stderr.puts "Error: #{arg}."
-    end
-    $stderr.puts "Try --help for help."
-    exit(-1)
-  end
-  
-  module_function :options, :die
-
-end # module