Class: RuboCop::Cop::Lint::MultipleComparison

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Defined in:
lib/rubocop/cop/lint/multiple_comparison.rb

Overview

In math and Python, we can use ‘x < y < z` style comparison to compare multiple values. However, we can’t use the comparison in Ruby. However, the comparison is not a syntax error. This cop checks the bad usage of comparison operators.

Examples:


# bad
x < y < z
10 <= x <= 20

# good
x < y && y < z
10 <= x && x <= 20

Constant Summary collapse

MSG = 
'Use the `&&` operator to compare multiple values.'
COMPARISON_METHODS = 
%i[< > <= >=].freeze
SET_OPERATION_OPERATORS = 
%i[& | ^].freeze
RESTRICT_ON_SEND = 
COMPARISON_METHODS

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source, #project_index

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, support_autocorrect?, support_multiple_source?, #target_gem_version, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

cop_dir_for, #exclude_limit, read_limits

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Instance Method Details

#multiple_compare?(node) ⇒ Object 



29
30
31
 
# File 'lib/rubocop/cop/lint/multiple_comparison.rb', line 29

def_node_matcher :multiple_compare?, <<~PATTERN
  (send (send _ {:< :> :<= :>=} $_) {:#{COMPARISON_METHODS.join(' :')}} _)
PATTERN

#on_send(node) ⇒ Object 



33
34
35
36
37
38
39
40
41
42
43
44
 
# File 'lib/rubocop/cop/lint/multiple_comparison.rb', line 33

def on_send(node)
  return unless (center = multiple_compare?(node))
  # It allows multiple comparison using `&`, `|`, and `^` set operation operators.
  # e.g. `x >= y & y < z`
  return if center.send_type? && SET_OPERATION_OPERATORS.include?(center.method_name)

  add_offense(node) do |corrector|
    new_center = "#{center.source} && #{center.source}"

    corrector.replace(center, new_center)
  end
end