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Class: RuboCop::Cop::Style::PerlBackrefs

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::AutoCorrector, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/perl_backrefs.rb

Overview

Looks for uses of Perl-style regexp match backreferences and their English versions like $1, $2, $&, &+, $MATCH, $PREMATCH, etc.

Examples:

# bad
puts $1

# good
puts Regexp.last_match(1)

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Returns an url to view this cops documentation online.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.

#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#constant_prefix(node) ⇒ String (private)

This method is for internal use only.

Parameters:

  • node (RuboCop::AST::Node)
[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 99

def constant_prefix(node)
  if node.each_ancestor(:class, :module).any?
    '::'
  else
    ''
  end
end

#derived_from_braceless_interpolation?(node) ⇒ Boolean (private)

This method is for internal use only.

Parameters:

  • node (RuboCop::AST::Node)
[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 38

def derived_from_braceless_interpolation?(node)
  %i[dstr regexp xstr].include?(node.parent&.type)
end

#format_message(node:, preferred_expression:) ⇒ String (private)

This method is for internal use only.

Parameters:

  • node (RuboCop::AST::Node)
  • preferred_expression (String)
[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 46

def format_message(node:, preferred_expression:)
  original_expression = original_expression_of(node)
  format(
    MESSAGE_FORMAT,
    original_expression: original_expression,
    preferred_expression: preferred_expression
  )
end

#on_back_ref(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 21

def on_back_ref(node)
  on_back_ref_or_gvar_or_nth_ref(node)
end

#on_back_ref_or_gvar_or_nth_ref(node) (private)

This method is for internal use only.

Parameters:

  • node (RuboCop::AST::Node)
[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 109

def on_back_ref_or_gvar_or_nth_ref(node)
  preferred_expression = preferred_expression_to_node_with_constant_prefix(node)
  return unless preferred_expression

  add_offense(
    node,
    message: format_message(node: node, preferred_expression: preferred_expression)
  ) do |corrector|
    if derived_from_braceless_interpolation?(node)
      preferred_expression = "{#{preferred_expression}}"
    end

    corrector.replace(node, preferred_expression)
  end
end

#on_gvar(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 25

def on_gvar(node)
  on_back_ref_or_gvar_or_nth_ref(node)
end

#on_nth_ref(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 29

def on_nth_ref(node)
  on_back_ref_or_gvar_or_nth_ref(node)
end

#original_expression_of(node) ⇒ String (private)

This method is for internal use only.

Parameters:

  • node (RuboCop::AST::Node)
[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 58

def original_expression_of(node)
  first = node.to_a.first
  if first.is_a?(::Integer)
    "$#{first}"
  else
    first.to_s
  end
end

#preferred_expression_to(node) ⇒ String? (private)

This method is for internal use only.

Parameters:

  • node (RuboCop::AST::Node)
[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 70

def preferred_expression_to(node)
  first = node.to_a.first
  case first
  when ::Integer
    "Regexp.last_match(#{first})"
  when :$&, :$MATCH
    'Regexp.last_match(0)'
  when :$`, :$PREMATCH
    'Regexp.last_match.pre_match'
  when :$', :$POSTMATCH
    'Regexp.last_match.post_match'
  when :$+, :$LAST_PAREN_MATCH
    'Regexp.last_match(-1)'
  end
end

#preferred_expression_to_node_with_constant_prefix(node) ⇒ String? (private)

This method is for internal use only.

Parameters:

  • node (RuboCop::AST::Node)
[ GitHub ]

  
# File 'lib/rubocop/cop/style/perl_backrefs.rb', line 89

def preferred_expression_to_node_with_constant_prefix(node)
  expression = preferred_expression_to(node)
  return unless expression

  "#{constant_prefix(node)}#{expression}"
end