lib/rubocop/cop/style/for.rb
# frozen_string_literal: true
module RuboCop
module Cop
module Style
# Looks for uses of the `for` keyword or `each` method. The
# preferred alternative is set in the EnforcedStyle configuration
# parameter. An `each` call with a block on a single line is always
# allowed.
#
# @example EnforcedStyle: each (default)
# # bad
# def foo
# for n in [1, 2, 3] do
# puts n
# end
# end
#
# # good
# def foo
# [1, 2, 3].each do |n|
# puts n
# end
# end
#
# @example EnforcedStyle: for
# # bad
# def foo
# [1, 2, 3].each do |n|
# puts n
# end
# end
#
# # good
# def foo
# for n in [1, 2, 3] do
# puts n
# end
# end
#
# @safety
# This cop's autocorrection is unsafe because the scope of
# variables is different between `each` and `for`.
#
class For < Base
include ConfigurableEnforcedStyle
include RangeHelp
extend AutoCorrector
EACH_LENGTH = 'each'.length
PREFER_EACH = 'Prefer `each` over `for`.'
PREFER_FOR = 'Prefer `for` over `each`.'
def on_for(node)
if style == :each
add_offense(node, message: PREFER_EACH) do |corrector|
ForToEachCorrector.new(node).call(corrector)
opposite_style_detected
end
else
correct_style_detected
end
end
def on_block(node)
return unless suspect_enumerable?(node)
if style == :for
return unless node.receiver
add_offense(node, message: PREFER_FOR) do |corrector|
EachToForCorrector.new(node).call(corrector)
opposite_style_detected
end
else
correct_style_detected
end
end
alias on_numblock on_block
private
def suspect_enumerable?(node)
node.multiline? && node.method?(:each) && !node.send_node.arguments?
end
end
end
end
end