Class: RuboCop::Cop::Performance::Casecmp

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/performance/casecmp.rb

Overview

This cop identifies places where a case-insensitive string comparison can better be implemented using ‘casecmp`.

Examples:

@bad
str.downcase == 'abc'
str.upcase.eql? 'ABC'
'abc' == str.downcase
'ABC'.eql? str.upcase
str.downcase == str.downcase

@good
str.casecmp('ABC').zero?
'abc'.casecmp(str).zero?

Constant Summary collapse

MSG = 
'Use `casecmp` instead of `%s %s`.'.freeze
CASE_METHODS = 
[:downcase, :upcase].freeze

Constants included from Util

Util::ASGN_NODES, Util::BYTE_ORDER_MARK, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, cop_type, #correct, #debug?, #details, #display_cop_names?, #display_style_guide?, #excluded_file?, #extra_details?, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #reference_url, #relevant_file?, #style_guide_url, #target_ruby_version

Methods included from Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search_body

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, comment_line?, directions, double_quotes_acceptable?, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, move_pos, needs_escaping?, numeric_range_size, on_node, operator?, parentheses?, parenthesized_call?, range_with_surrounding_comma, range_with_surrounding_space, source_range, strip_quotes, to_string_literal, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, match_path?, relative_path

Constructor Details

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

Instance Method Details

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/casecmp.rb', line 61

def autocorrect(node)
  downcase_eq(node) do
    receiver, method, arg = *node
    variable, = *receiver
    return correction(node, receiver, method, arg, variable)
  end

  eq_downcase(node) do
    arg, method, receiver = *node
    variable, = *receiver
    return correction(node, receiver, method, arg, variable)
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/casecmp.rb', line 39

def on_send(node)
  return if part_of_ignored_node?(node)

  downcase_eq(node) do |send_downcase, case_method, eq_method, other|
    *_, method = *other
    if CASE_METHODS.include?(method)
      range = node.loc.expression
      ignore_node(node)
    else
      range = node.loc.selector.join(send_downcase.loc.selector)
    end

    add_offense(node, range, format(MSG, case_method, eq_method))
    return
  end

  eq_downcase(node) do |eq_method, send_downcase, case_method|
    range = node.loc.selector.join(send_downcase.loc.selector)
    add_offense(node, range, format(MSG, eq_method, case_method))
  end
end