class Trollop::Parser

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.

Constants

FLAG_TYPES

The set of values that indicate a flag option when passed as the :type parameter of opt.

MULTI_ARG_TYPES

The set of values that indicate a multiple-parameter option (i.e., that takes multiple space-separated values on the commandline) when passed as the :type parameter of opt.

SINGLE_ARG_TYPES

The set of values that indicate a single-parameter (normal) 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 ‘-’.

TYPES

The complete set of legal values for the :type parameter of opt.

Attributes

leftovers [R]

The values from the commandline that were not interpreted by parse.

specs [R]

The complete configuration hashes for each option. (Mainly useful for testing.)

Public Class Methods

new (*a, &b)

Source

# File lib/trollop.rb, line 69
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

Initializes the parser, and instance-evaluates any block given.

Public Instance Methods

conflicts (*syms)

Source

# File lib/trollop.rb, line 254
def conflicts *syms
  syms.each { |sym| raise ArgumentError, "unknown option '#{sym}'" unless @specs[sym] }
  @constraints << [:conflicts, syms]
end

Marks two (or more!) options as conflicting.

depends (*syms)

Source

# File lib/trollop.rb, line 248
def depends *syms
  syms.each { |sym| raise ArgumentError, "unknown option '#{sym}'" unless @specs[sym] }
  @constraints << [:depends, syms]
end

Marks two (or more!) options as requiring each other. Only handles undirected (i.e., mutual) dependencies. Directed dependencies are better modeled with Trollop::die.

educate (stream=$stdout)

Source

# File lib/trollop.rb, line 415
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+>"
      when :date; " <date>"
      when :dates; " <date+>"
      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

Print the help message to stream.

opt (name, desc="", opts={})

Source

# File lib/trollop.rb, line 124
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].name
      when 'TrueClass', 'FalseClass'; :flag
      when 'String'; :string
      when 'Integer'; :int
      when 'Float'; :float
      when 'IO'; :io
      when 'Date'; :date
      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 Date; :date
    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
      when Date; :dates
      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 (default type is #{type_from_default})" 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

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. In contrast with regular non-multi options, if not specified on the commandline, the default value will be [], not nil.

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.

parse (cmdline=ARGV)

Source

# File lib/trollop.rb, line 281
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]
    vals[sym] = [] if opts[:multi] && !opts[:default] # multi arguments default to [], not nil
  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 } }
    when :date, :dates
      vals[sym] = params.map { |pg| pg.map { |p| parse_date_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

Parses the commandline. Typically called by Trollop::options.

stop_on (*words)

Source

# File lib/trollop.rb, line 268
def stop_on *words
  @stop_words = [*words].flatten
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.

stop_on_unknown ()

Source

# File lib/trollop.rb, line 276
def stop_on_unknown
  @stop_on_unknown = true
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.

text (s;)

Alias for: banner

version (s=nil;)

Source

# File lib/trollop.rb, line 238
def version s=nil; @version = s if s; @version 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>”.