Class: RuboCop::Cop::Style::NumericPredicate

Inherits:
Cop
  • Object
show all
Includes:
ConfigurableEnforcedStyle, IgnoredMethods
Defined in:
lib/rubocop/cop/style/numeric_predicate.rb

Overview

This cop checks for usage of comparison operators (‘==`, `>`, `<`) to test numbers as zero, positive, or negative. These can be replaced by their respective predicate methods. The cop can also be configured to do the reverse.

The cop disregards ‘#nonzero?` as it its value is truthy or falsey, but not `true` and `false`, and thus not always interchangeable with `!= 0`.

The cop ignores comparisons to global variables, since they are often populated with objects which can be compared with integers, but are not themselves ‘Integer` polymorphic.

Examples:

EnforcedStyle: predicate (default)

# bad

foo == 0
0 > foo
bar.baz > 0

# good

foo.zero?
foo.negative?
bar.baz.positive?

EnforcedStyle: comparison

# bad

foo.zero?
foo.negative?
bar.baz.positive?

# good

foo == 0
0 > foo
bar.baz > 0

Constant Summary collapse

MSG = 
'Use `%<prefer>s` instead of `%<current>s`.'
REPLACEMENTS = 
{
  'zero?' => '==',
  'positive?' => '>',
  'negative?' => '<'
}.freeze

Constants included from Util

Util::LITERAL_REGEX

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods included from ConfigurableEnforcedStyle

#alternative_style, #alternative_styles, #ambiguous_style_detected, #correct_style_detected, #detected_style, #detected_style=, #no_acceptable_style!, #no_acceptable_style?, #opposite_style_detected, #style, #style_detected, #style_parameter_name, #supported_styles, #unexpected_style_detected

Methods inherited from Cop

#add_offense, all, autocorrect_incompatible_with, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, #correct, department, #disable_uncorrectable, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, #parse, qualified_cop_name, #reason_to_not_correct, #relevant_file?, #target_rails_version, #target_ruby_version

Methods included from AST::Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #correctable?, #disable_offense, #disable_uncorrectable?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, comment_line?, double_quotes_required?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, needs_escaping?, on_node, parentheses?, same_line?, to_string_literal, to_supported_styles, tokens, trim_string_interporation_escape_character

Methods included from PathUtil

absolute?, chdir, hidden_dir?, hidden_file_in_not_hidden_dir?, match_path?, pwd, relative_path, reset_pwd, smart_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/style/numeric_predicate.rb', line 71

def autocorrect(node)
  _, replacement = check(node)

  lambda do |corrector|
    corrector.replace(node.loc.expression, replacement)
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/numeric_predicate.rb', line 56

def on_send(node)
  return if node.each_ancestor(:send, :block).any? do |ancestor|
    ignored_method?(ancestor.method_name)
  end

  numeric, replacement = check(node)

  return unless numeric

  add_offense(node,
              message: format(MSG,
                              prefer: replacement,
                              current: node.source))
end