Class: RuboCop::Cop::Performance::RegexpMatch

Inherits:
Cop
  • Object
show all
Extended by:
TargetRubyVersion
Defined in:
lib/rubocop/cop/performance/regexp_match.rb

Overview

In Ruby 2.4, ‘String#match?`, `Regexp#match?` and `Symbol#match?` have been added. The methods are faster than `match`. Because the methods avoid creating a `MatchData` object or saving backref. So, when `MatchData` is not used, use `match?` instead of `match`.

Examples:

# bad
def foo
  if x =~ /re/
    do_something
  end
end

# bad
def foo
  if x !~ /re/
    do_something
  end
end

# bad
def foo
  if x.match(/re/)
    do_something
  end
end

# bad
def foo
  if /re/ === x
    do_something
  end
end

# good
def foo
  if x.match?(/re/)
    do_something
  end
end

# good
def foo
  if !x.match?(/re/)
    do_something
  end
end

# good
def foo
  if x =~ /re/
    do_something(Regexp.last_match)
  end
end

# good
def foo
  if x.match(/re/)
    do_something($~)
  end
end

# good
def foo
  if /re/ === x
    do_something($~)
  end
end

Constant Summary collapse

TYPES_IMPLEMENTING_MATCH =

Constants are included in this list because it is unlikely that someone will store ‘nil` as a constant and then use it for comparison

%i[const regexp str sym].freeze
MSG = 
'Use `match?` instead of `%<current>s` when `MatchData` ' \
'is not used.'.freeze
MATCH_NODE_PATTERN = 
<<-PATTERN.freeze
  {
    #match_method?
    #match_operator?
    #match_threequals?
    #match_with_lvasgn?
  }
PATTERN

Constants included from Util

Util::ASGN_NODES, Util::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods included from TargetRubyVersion

minimum_target_ruby_version, support_target_ruby_version?

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, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #messages, non_rails, #parse, qualified_cop_name, #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?, #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, operator?, parentheses?, same_line?, to_string_literal, to_supported_styles, tokens

Methods included from PathUtil

absolute?, 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/performance/regexp_match.rb', line 143

def autocorrect(node)
  lambda do |corrector|
    if match_method?(node)
      corrector.replace(node.loc.selector, 'match?')
    elsif match_operator?(node) || match_threequals?(node)
      recv, oper, arg = *node
      correct_operator(corrector, recv, arg, oper)
    elsif match_with_lvasgn?(node)
      recv, arg = *node
      correct_operator(corrector, recv, arg)
    end
  end
end

#match_with_lvasgn?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/performance/regexp_match.rb', line 102

def match_with_lvasgn?(node)
  return false unless node.match_with_lvasgn_type?
  regexp, _rhs = *node
  regexp.to_regexp.named_captures.empty?
end

#on_case(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/regexp_match.rb', line 133

def on_case(node)
  return if node.condition

  node.each_when do |when_node|
    when_node.each_condition do |condition|
      check_condition(condition)
    end
  end
end

#on_if(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/regexp_match.rb', line 129

def on_if(node)
  check_condition(node.condition)
end