class RuboCop::Cop::Style::SpecialGlobalVars

Looks for uses of Perl-style global variables. Correcting to global variables in the ‘English’ library will add a require statement to the top of the file if enabled by RequireEnglish config.

@safety

Autocorrection is marked as unsafe because if `RequireEnglish` is not
true, replacing perl-style variables with english variables will break.

@example EnforcedStyle: use_english_names (default)

# good
require 'English' # or this could be in another file.

puts $LOAD_PATH
puts $LOADED_FEATURES
puts $PROGRAM_NAME
puts $ERROR_INFO
puts $ERROR_POSITION
puts $FIELD_SEPARATOR # or $FS
puts $OUTPUT_FIELD_SEPARATOR # or $OFS
puts $INPUT_RECORD_SEPARATOR # or $RS
puts $OUTPUT_RECORD_SEPARATOR # or $ORS
puts $INPUT_LINE_NUMBER # or $NR
puts $LAST_READ_LINE
puts $DEFAULT_OUTPUT
puts $DEFAULT_INPUT
puts $PROCESS_ID # or $PID
puts $CHILD_STATUS
puts $LAST_MATCH_INFO
puts $IGNORECASE
puts $ARGV # or ARGV

@example EnforcedStyle: use_perl_names

# good
puts $:
puts $"
puts $0
puts $!
puts $@
puts $;
puts $,
puts $/
puts $\
puts $.
puts $_
puts $>
puts $<
puts $$
puts $?
puts $~
puts $=
puts $*

@example EnforcedStyle: use_builtin_english_names

# good
# Like `use_perl_names` but allows builtin global vars.
puts $LOAD_PATH
puts $LOADED_FEATURES
puts $PROGRAM_NAME
puts ARGV
puts $:
puts $"
puts $0
puts $!
puts $@
puts $;
puts $,
puts $/
puts $\
puts $.
puts $_
puts $>
puts $<
puts $$
puts $?
puts $~
puts $=
puts $*

Constants

BUILTIN_VARS
ENGLISH_VARS
LIBRARY_NAME
MSG_BOTH
MSG_ENGLISH
MSG_REGULAR
NON_ENGLISH_VARS

Anything not in this set is provided by the English library.

PERL_VARS
STYLE_VARS_MAP

Public Instance Methods

autocorrect(corrector, node, global_var) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 175
def autocorrect(corrector, node, global_var)
  node = node.parent while node.parent&.begin_type? && node.parent.children.one?

  if should_require_english?(global_var)
    ensure_required(corrector, node, LIBRARY_NAME)

    @required_english = true
  end

  corrector.replace(node, replacement(node, global_var))
end
message(global_var) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 167
def message(global_var)
  if style == :use_english_names
    format_english_message(global_var)
  else
    format(MSG_REGULAR, prefer: preferred_names(global_var).first, global: global_var)
  end
end
on_gvar(node) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 151
def on_gvar(node)
  global_var, = *node

  return unless (preferred = preferred_names(global_var))

  if preferred.include?(global_var)
    correct_style_detected
  else
    style_detected(matching_styles(global_var))

    add_offense(node, message: message(global_var)) do |corrector|
      autocorrect(corrector, node, global_var)
    end
  end
end
on_new_investigation() click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 146
def on_new_investigation
  super
  @required_english = false
end

Private Instance Methods

add_require_english?() click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 246
def add_require_english?
  cop_config['RequireEnglish']
end
english_name_replacement(preferred_name, node) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 240
def english_name_replacement(preferred_name, node)
  return "\#{#{preferred_name}}" if node.begin_type?

  "{#{preferred_name}}"
end
format_english_message(global_var) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 189
def format_english_message(global_var)
  regular, english = ENGLISH_VARS[global_var].partition do |var|
    NON_ENGLISH_VARS.include? var
  end

  format_message(english, regular, global_var)
end
format_list(items) click to toggle source

For now, we assume that lists are 2 items or less. Easy grammar!

# File lib/rubocop/cop/style/special_global_vars.rb, line 211
def format_list(items)
  items.join('` or `')
end
format_message(english, regular, global) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 197
def format_message(english, regular, global)
  if regular.empty?
    format(MSG_ENGLISH, prefer: format_list(english), global: global)
  elsif english.empty?
    format(MSG_REGULAR, prefer: format_list(regular), global: global)
  else
    format(MSG_BOTH,
           prefer: format_list(english),
           regular: format_list(regular),
           global: global)
  end
end
matching_styles(global) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 234
def matching_styles(global)
  STYLE_VARS_MAP.filter_map do |style, vars|
    style if vars.values.flatten(1).include? global
  end
end
preferred_names(global) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 226
def preferred_names(global)
  vars = STYLE_VARS_MAP.fetch(style) do
    raise ArgumentError, "Invalid style: #{style.inspect}"
  end

  vars[global]
end
replacement(node, global_var) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 215
def replacement(node, global_var)
  parent_type = node.parent&.type
  preferred_name = preferred_names(global_var).first

  return preferred_name.to_s unless %i[dstr xstr regexp].include?(parent_type)

  return english_name_replacement(preferred_name, node) if style == :use_english_names

  "##{preferred_name}"
end
should_require_english?(global_var) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 250
def should_require_english?(global_var)
  style == :use_english_names &&
    add_require_english? &&
    !@required_english &&
    !NON_ENGLISH_VARS.include?(preferred_names(global_var).first)
end