class RuboCop::Cop::Style::SpecialGlobalVars

This cop looks for uses of Perl-style global variables.

@example EnforcedStyle: use_english_names (default)

# good
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
puts $MATCH
puts $PREMATCH
puts $POSTMATCH
puts $LAST_PAREN_MATCH

@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 $*
puts $&
puts $`
puts $'
puts $+

Constants

ENGLISH_VARS
MSG_BOTH
MSG_ENGLISH
MSG_REGULAR
NON_ENGLISH_VARS

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

PERL_VARS

Public Instance Methods

autocorrect(node) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 139
def autocorrect(node)
  lambda do |corrector|
    global_var, = *node

    while node.parent&.begin_type? &&
          node.parent.children.one?
      node = node.parent
    end

    corrector.replace(node.source_range, replacement(node, global_var))
  end
end
message(node) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 127
def message(node)
  global_var, = *node

  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 114
def on_gvar(node)
  global_var, = *node

  return unless (preferred = preferred_names(global_var))

  if preferred.include?(global_var)
    correct_style_detected
  else
    opposite_style_detected
    add_offense(node)
  end
end

Private Instance Methods

english_name_replacement(preferred_name, node) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 205
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 154
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 178
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 162
def format_message(english, regular, global)
  if !regular.empty? && !english.empty?
    format(MSG_BOTH,
           prefer: format_list(english),
           regular: format_list(regular),
           global: global)
  elsif !regular.empty?
    format(MSG_REGULAR, prefer: format_list(regular), global: global)
  elsif !english.empty?
    format(MSG_ENGLISH, prefer: format_list(english), global: global)
  else
    raise 'Bug in SpecialGlobalVars - global var w/o preferred vars!'
  end
end
preferred_names(global) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 197
def preferred_names(global)
  if style == :use_english_names
    ENGLISH_VARS[global]
  else
    PERL_VARS[global]
  end
end
replacement(node, global_var) click to toggle source
# File lib/rubocop/cop/style/special_global_vars.rb, line 182
def replacement(node, global_var)
  parent_type = node.parent&.type
  preferred_name = preferred_names(global_var).first

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

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

  "##{preferred_name}"
end