Class: OptionsByExample::UsageSpecification

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(text) ⇒ UsageSpecification

Returns a new instance of UsageSpecification.



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# File 'lib/options_by_example/usage_specification.rb', line 11

def initialize(text)
  @message = text.gsub('$0', File.basename($0)).gsub(/\n+\Z/, "\n\n")

  # --- 1) Parse argument names -------------------------------------
  #
  # Parse the usage string and extract both optional argument names
  # and required argument names, for example:
  #
  # Usage: connect [options] [mode] host port

  @argument_names = {}
  inline_options = []

  usage_line = text.lines.grep(/Usage:/).first
  raise "Expected usage string, got none" unless usage_line
  tokens = usage_line.split(/(\[.*?\]?\]|\w+ \.\.\.)|\s+/).reject(&:empty?)
  raise "Expected usage line to start with 'Usage:'" unless tokens.shift == 'Usage:'
  raise "Expected command name on same line as 'Usage:'" unless tokens.shift
  tokens.shift if tokens.first == '[options]'

  while /^\[(--?\w.*)\]$/ === tokens.first
    inline_options << $1
    tokens.shift
  end

  while /^(\w+)( ?\.\.\.)?$/ === tokens.first
    vararg_if_dotted = $2 ? :vararg : :required
    @argument_names[sanitize $1] = vararg_if_dotted
    tokens.shift
  end

  while /^\[(\w+)\]$/ === tokens.first
    @argument_names[sanitize $1] = :optional
    tokens.shift
  end

  if /^\[(\w+) ?\.\.\.\]$/ === tokens.first
    @argument_names[sanitize $1] = :optional_vararg
    tokens.shift
  end

  raise "Found invalid usage token '#{tokens.first}'" unless tokens.empty?

  if count_arguments(:vararg) > 0 && count_arguments(/optional/) > 0
    raise "Cannot combine vararg and optional arguments"
  end

  if count_arguments(/vararg/) > 1
    raise "Found more than one vararg arguments"
  end

  # --- 2) Parse option names ---------------------------------------
  #
  # Parse the usage message and extract option names, their short and
  # long forms, and the associated argument name (if any), eg:
  #
  # Options:
  #   -s, --secure        Use secure connection
  #   -v, --verbose       Enable verbose output
  #   -r, --retries NUM   Number of connection retries (default 3)
  #   -t, --timeout NUM   Set connection timeout in seconds

  @option_names = {}

  options = inline_options + text.lines.grep(/^\s*--?\w/)
  options.each do |string|
    tokens = string.strip.split(/(\s+)|(,)\s*/)

    short_form = nil
    long_form = nil
    option_name = nil
    argument_arity = nil
    argument_type = nil
    default_value = nil

    if /^-(\w)$/ === tokens.first
      short_form = tokens.shift
      option_name = sanitize $1
      tokens.shift if tokens.first == ','
    end

    if /^--([\w-]+)$/ === tokens.first
      long_form = tokens.shift
      option_name = sanitize $1
    end

    if tokens.shift == ' '
      if /^(\[(.+)\]|(.+)\?)$/ === tokens.first
        argument_type = $2 || $3
        argument_arity = :optional
        tokens.shift
      else
        argument_type = tokens.shift
        argument_arity = :required
      end
    end

    if /\(default\s+(\S+)\)$/ === tokens.join
      default_value = $1
    end

    ary = [option_name, argument_arity, argument_type, default_value]
    [short_form, long_form].each do |each|
      @option_names[each] = ary if each
    end
  end
end

Instance Attribute Details

#argument_names ⇒ Object (readonly)

Returns the value of attribute argument_names.



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# File 'lib/options_by_example/usage_specification.rb', line 8

def argument_names
  @argument_names
end

#message ⇒ Object (readonly)

Returns the value of attribute message.



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# File 'lib/options_by_example/usage_specification.rb', line 7

def message
  @message
end

#option_names ⇒ Object (readonly)

Returns the value of attribute option_names.



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# File 'lib/options_by_example/usage_specification.rb', line 9

def option_names
  @option_names
end