Class: Trollop::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/trollop.rb

Overview

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 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 Trollop::with_standard_exception_handling.

Constant Summary collapse

INVALID_SHORT_ARG_REGEX =

:nodoc:

/[\d-]/

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*a, &b) ⇒ Parser

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



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# File 'lib/trollop.rb', line 90

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

Instance Attribute Details

#ignore_invalid_options ⇒ Object

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.



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# File 'lib/trollop.rb', line 87

def ignore_invalid_options
  @ignore_invalid_options
end

#leftovers ⇒ Object (readonly)

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



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# File 'lib/trollop.rb', line 78

def leftovers
  @leftovers
end

#specs ⇒ Object (readonly)

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



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# File 'lib/trollop.rb', line 82

def specs
  @specs
end

Class Method Details

.register(lookup, klass) ⇒ Object

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



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# File 'lib/trollop.rb', line 57

def self.register(lookup, klass)
  @registry[lookup.to_sym] = klass
end

.registry_getopttype(type) ⇒ Object

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

Raises:

  • (ArgumentError) 


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# File 'lib/trollop.rb', line 63

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

Instance Method Details

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



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# File 'lib/trollop.rb', line 185

def banner(s)
  @order << [:text, s]
end

#conflicts(*syms) ⇒ Object

Marks two (or more!) options as conflicting.



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# File 'lib/trollop.rb', line 199

def conflicts(*syms)
  syms.each { |sym| raise ArgumentError, "unknown option '#{sym}'" unless @specs[sym] }
  @constraints << [:conflicts, syms]
end

#depends(*syms) ⇒ Object

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



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# File 'lib/trollop.rb', line 193

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) ⇒ Object

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



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# File 'lib/trollop.rb', line 429

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) ⇒ Object

Print the help message to stream.



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# File 'lib/trollop.rb', line 360

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 ⇒ Object

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



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# File 'lib/trollop.rb', line 227

def educate_on_error
  @educate_on_error = true
end

#opt(name, desc = "", opts = {}, &b) ⇒ Object

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 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.

Raises:

  • (ArgumentError) 


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# File 'lib/trollop.rb', line 148

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) ⇒ Object

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

throws CommandlineError, HelpNeeded, and VersionNeeded exceptions.

Raises:



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# File 'lib/trollop.rb', line 235

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) ⇒ Object

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.



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# File 'lib/trollop.rb', line 213

def stop_on(*words)
  @stop_words = [*words].flatten
end

#stop_on_unknown ⇒ Object

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.



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# File 'lib/trollop.rb', line 221

def stop_on_unknown
  @stop_on_unknown = true
end

#synopsis(s = nil) ⇒ Object

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



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# File 'lib/trollop.rb', line 179

def synopsis(s = nil)
  s ? @synopsis = s : @synopsis
end

#usage(s = nil) ⇒ Object

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.



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# File 'lib/trollop.rb', line 173

def usage(s = nil)
  s ? @usage = s : @usage
end

#version(s = nil) ⇒ Object

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>”.



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# File 'lib/trollop.rb', line 166

def version(s = nil)
  s ? @version = s : @version
end

#width ⇒ Object

:nodoc:



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# File 'lib/trollop.rb', line 393

def width #:nodoc:
  @width ||= if $stdout.tty?
    begin
      require 'io/console'
      w = IO.console.winsize.last
      w.to_i > 0 ? w : 80
    rescue LoadError, NoMethodError, Errno::ENOTTY, Errno::EBADF, Errno::EINVAL
      legacy_width
    end
  else
    80
  end
end

#wrap(str, opts = {}) ⇒ Object

:nodoc:



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# File 'lib/trollop.rb', line 415

def wrap(str, opts = {}) # :nodoc:
  if str == ""
    [""]
  else
    inner = false
    str.split("\n").map do |s|
      line = wrap_line s, opts.merge(:inner => inner)
      inner = true
      line
    end.flatten
  end
end