class Optimist::Parser

The commandline parser. In typical usage, the methods in this class will be handled internally by Optimist::options. In this case, only the opt, banner and version, depends, and conflicts methods will typically be called.

If you want to instantiate this class yourself (for more complicated argument-parsing logic), call parse to actually produce the output hash, and consider calling it from within Optimist::with_standard_exception_handling.

Attributes

ignore_invalid_options[RW]

A flag that determines whether or not to raise an error if the parser is passed one or more

options that were not registered ahead of time.  If 'true', then the parser will simply
ignore options that it does not recognize.
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) click to toggle source

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

# File lib/optimist.rb, line 88
def initialize(*a, &b)
  @version = nil
  @leftovers = []
  @specs = {}
  @long = {}
  @short = {}
  @order = []
  @constraints = []
  @stop_words = []
  @stop_on_unknown = false
  @educate_on_error = false
  @synopsis = nil
  @usage = nil

  # instance_eval(&b) if b # can't take arguments
  cloaker(&b).bind(self).call(*a) if b
end
register(lookup, klass) click to toggle source

The Option subclasses are responsible for registering themselves using this function.

# File lib/optimist.rb, line 55
def self.register(lookup, klass)
  @registry[lookup.to_sym] = klass
end
registry_getopttype(type) click to toggle source

Gets the class from the registry. Can be given either a class-name, e.g. Integer, a string, e.g “integer”, or a symbol, e.g :integer

# File lib/optimist.rb, line 61
def self.registry_getopttype(type)
  return nil unless type
  if type.respond_to?(:name)
    type = type.name
    lookup = type.downcase.to_sym
  else
    lookup = type.to_sym
  end
  raise ArgumentError, "Unsupported argument type '#{type}', registry lookup '#{lookup}'" unless @registry.has_key?(lookup)
  return @registry[lookup].new
end

Public Instance Methods

banner(s) click to toggle source

Adds text to the help display. Can be interspersed with calls to opt to build a multi-section help page.

Also aliased as: text
conflicts(*syms) click to toggle source

Marks two (or more!) options as conflicting.

# File lib/optimist.rb, line 197
def conflicts(*syms)
  syms.each { |sym| raise ArgumentError, "unknown option '#{sym}'" unless @specs[sym] }
  @constraints << [:conflicts, syms]
end
depends(*syms) click to toggle source

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

# File lib/optimist.rb, line 191
def depends(*syms)
  syms.each { |sym| raise ArgumentError, "unknown option '#{sym}'" unless @specs[sym] }
  @constraints << [:depends, syms]
end
die(arg, msg = nil, error_code = nil) click to toggle source

The per-parser version of Optimist::die (see that for documentation).

# File lib/optimist.rb, line 427
def die(arg, msg = nil, error_code = nil)
  msg, error_code = nil, msg if msg.kind_of?(Integer)
  if msg
    $stderr.puts "Error: argument --#{@specs[arg].long} #{msg}."
  else
    $stderr.puts "Error: #{arg}."
  end
  if @educate_on_error
    $stderr.puts
    educate $stderr
  else
    $stderr.puts "Try --help for help."
  end
  exit(error_code || -1)
end
educate(stream = $stdout) click to toggle source

Print the help message to stream.

# File lib/optimist.rb, line 358
def educate(stream = $stdout)
  width # hack: 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 { |name, spec| left[name] = spec.educate }

  leftcol_width = left.values.map(&:length).max || 0
  rightcol_start = leftcol_width + 6 # spaces

  unless @order.size > 0 && @order.first.first == :text
    command_name = File.basename($0).gsub(/\.[^.]+$/, '')
    stream.puts "Usage: #{command_name} #{@usage}\n" if @usage
    stream.puts "#{@synopsis}\n" if @synopsis
    stream.puts if @usage || @synopsis
    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.description_with_default

    stream.puts wrap(desc, :width => width - rightcol_start - 1, :prefix => rightcol_start)
  end
end
educate_on_error() click to toggle source

Instead of displaying “Try –help for help.” on an error display the usage (via educate)

# File lib/optimist.rb, line 225
def educate_on_error
  @educate_on_error = true
end
opt(name, desc = "", opts = {}, &b) click to toggle source

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. Use :none: to not have a short value.

: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 Optimist::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, Optimist 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.

# File lib/optimist.rb, line 146
def opt(name, desc = "", opts = {}, &b)
  opts[:callback] ||= b if block_given?
  opts[:desc] ||= desc

  o = Option.create(name, desc, opts)

  raise ArgumentError, "you already have an argument named '#{name}'" if @specs.member? o.name
  raise ArgumentError, "long option name #{o.long.inspect} is already taken; please specify a (different) :long" if @long[o.long]
  raise ArgumentError, "short option name #{o.short.inspect} is already taken; please specify a (different) :short" if @short[o.short]
  @long[o.long] = o.name
  @short[o.short] = o.name if o.short?
  @specs[o.name] = o
  @order << [:opt, o.name]
end
parse(cmdline = ARGV) click to toggle source

Parses the commandline. Typically called by Optimist::options, but you can call it directly if you need more control.

throws CommandlineError, HelpNeeded, and VersionNeeded exceptions.

# File lib/optimist.rb, line 233
def parse(cmdline = ARGV)
  vals = {}
  required = {}

  opt :version, "Print version and exit" if @version && ! (@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|
    ## handle --no- forms
    arg, negative_given = if arg =~ /^--no-([^-]\S*)$/
      ["--#{$1}", true]
    else
      [arg, false]
    end

    sym = case arg
      when /^-([^-])$/      then @short[$1]
      when /^--([^-]\S*)$/  then @long[$1] || @long["no-#{$1}"]
      else                       raise CommandlineError, "invalid argument syntax: '#{arg}'"
    end

    sym = nil if arg =~ /--no-/ # explicitly invalidate --no-no- arguments

    next nil if ignore_invalid_options && !sym
    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][:negative_given] = negative_given
    given_args[sym][:params] ||= []

    # The block returns the number of parameters taken.
    num_params_taken = 0

    unless params.empty?
      if @specs[sym].single_arg?
        given_args[sym][:params] << params[0, 1]  # take the first parameter
        num_params_taken = 1
      elsif @specs[sym].multi_arg?
        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 --#{@specs[sym].long} must be specified" unless given_args.include? sym
  end

  ## parse parameters
  given_args.each do |sym, given_data|
    arg, params, negative_given = given_data.values_at :arg, :params, :negative_given

    opts = @specs[sym]
    if params.empty? && !opts.flag?
      raise CommandlineError, "option '#{arg}' needs a parameter" unless opts.default
      params << (opts.array_default? ? opts.default.clone : [opts.default])
    end

    vals["#{sym}_given".intern] = true # mark argument as specified on the commandline

    vals[sym] = opts.parse(params, negative_given)

    if opts.single_arg?
      if opts.multi?        # multiple options, each with a single parameter
        vals[sym] = vals[sym].map { |p| p[0] }
      else                  # single parameter
        vals[sym] = vals[sym][0][0]
      end
    elsif opts.multi_arg? && !opts.multi?
      vals[sym] = vals[sym][0]  # single option, with multiple parameters
    end
    # else: multiple options, with multiple parameters

    opts.callback.call(vals[sym]) if opts.callback
  end

  ## modify input in place with only those
  ## arguments we didn't process
  cmdline.clear
  @leftovers.each { |l| cmdline << l }

  ## allow openstruct-style accessors
  class << vals
    def method_missing(m, *_args)
      self[m] || self[m.to_s]
    end
  end
  vals
end
stop_on(*words) click to toggle source

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 Optimist invocation would then be used to parse subcommand options, after shifting the subcommand off of ARGV.

# File lib/optimist.rb, line 211
def stop_on(*words)
  @stop_words = [*words].flatten
end
stop_on_unknown() click to toggle source

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.

# File lib/optimist.rb, line 219
def stop_on_unknown
  @stop_on_unknown = true
end
synopsis(s = nil) click to toggle source

Adds a synopsis (command summary description) right below the usage line, or as the first line if usage isn't specified.

# File lib/optimist.rb, line 177
def synopsis(s = nil)
  s ? @synopsis = s : @synopsis
end
text(s)
Alias for: banner
usage(s = nil) click to toggle source

Sets the usage string. If set the message will be printed as the first line in the help (educate) output and ending in two new lines.

# File lib/optimist.rb, line 171
def usage(s = nil)
  s ? @usage = s : @usage
end
version(s = nil) click to toggle source

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>”.

# File lib/optimist.rb, line 164
def version(s = nil)
  s ? @version = s : @version
end

Private Instance Methods

cloaker(&b) click to toggle source

instance_eval but with ability to handle block arguments thanks to _why: redhanded.hobix.com/inspect/aBlockCostume.html

# File lib/optimist.rb, line 568
def cloaker(&b)
  (class << self; self; end).class_eval do
    define_method :cloaker_, &b
    meth = instance_method :cloaker_
    remove_method :cloaker_
    meth
  end
end
collect_argument_parameters(args, start_at) click to toggle source
# File lib/optimist.rb, line 523
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
each_arg(args) { |"--#{$1}", [$2]| ... } click to toggle source

yield successive arg, parameter pairs

# File lib/optimist.rb, line 446
def each_arg(args)
  remains = []
  i = 0

  until i >= args.length
    return remains += args[i..-1] if @stop_words.member? args[i]
    case args[i]
    when /^--$/ # arg terminator
      return remains += args[(i + 1)..-1]
    when /^--(\S+?)=(.*)$/ # long argument with equals
      num_params_taken = yield "--#{$1}", [$2]
      if num_params_taken.nil?
        remains << args[i]
        if @stop_on_unknown
          return remains += args[i + 1..-1]
        end
      end
      i += 1
    when /^--(\S+)$/ # long argument
      params = collect_argument_parameters(args, i + 1)
      num_params_taken = yield args[i], params

      if num_params_taken.nil?
        remains << args[i]
        if @stop_on_unknown
          return remains += args[i + 1..-1]
        end
      else
        i += num_params_taken
      end
      i += 1
    when /^-(\S+)$/ # one or more short arguments
      short_remaining = ""
      shortargs = $1.split(//)
      shortargs.each_with_index do |a, j|
        if j == (shortargs.length - 1)
          params = collect_argument_parameters(args, i + 1)

          num_params_taken = yield "-#{a}", params
          unless num_params_taken
            short_remaining << a
            if @stop_on_unknown
              remains << "-#{short_remaining}"
              return remains += args[i + 1..-1]
            end
          else
            i += num_params_taken
          end
        else
          unless yield "-#{a}", []
            short_remaining << a
            if @stop_on_unknown
              short_remaining += shortargs[j + 1..-1].join
              remains << "-#{short_remaining}"
              return remains += args[i + 1..-1]
            end
          end
        end
      end

      unless short_remaining.empty?
        remains << "-#{short_remaining}"
      end
      i += 1
    else
      if @stop_on_unknown
        return remains += args[i..-1]
      else
        remains << args[i]
        i += 1
      end
    end
  end

  remains
end
legacy_width() click to toggle source
# File lib/optimist.rb, line 405
def legacy_width
  # Support for older Rubies where io/console is not available
  `tput cols`.to_i
rescue Errno::ENOENT
  80
end
resolve_default_short_options!() click to toggle source
# File lib/optimist.rb, line 533
def resolve_default_short_options!
  @order.each do |type, name|
    opts = @specs[name]
    next if type != :opt || opts.short

    c = opts.long.split(//).find { |d| d !~ INVALID_SHORT_ARG_REGEX && !@short.member?(d) }
    if c # found a character to use
      opts.short = c
      @short[c] = name
    end
  end
end
wrap_line(str, opts = {}) click to toggle source
# File lib/optimist.rb, line 546
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? && !opts[:inner]) ? "" : " " * prefix) + str[start...nextt]
    start = nextt + 1
  end
  ret
end