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Contents
# frozen_string_literal: true
module RuboCop
module Cop
module Lint
# Don't omit the accumulator when calling `next` in a `reduce` block.
#
# @example
#
# # bad
#
# result = (1..4).reduce(0) do |acc, i|
# next if i.odd?
# acc + i
# end
#
# @example
#
# # good
#
# result = (1..4).reduce(0) do |acc, i|
# next acc if i.odd?
# acc + i
# end
class NextWithoutAccumulator < Base
MSG = 'Use `next` with an accumulator argument in a `reduce`.'
def on_block(node)
on_block_body_of_reduce(node) do |body|
void_next = body.each_node(:next).find do |n|
n.children.empty? && parent_block_node(n) == node
end
add_offense(void_next) if void_next
end
end
def on_numblock(node)
on_numblock_body_of_reduce(node) do |body|
void_next = body.each_node(:next).find do |n|
n.children.empty? && parent_numblock_node(n) == node
end
add_offense(void_next) if void_next
end
end
private
# @!method on_block_body_of_reduce(node)
def_node_matcher :on_block_body_of_reduce, <<~PATTERN
(block (send _recv {:reduce :inject} !sym) _blockargs $(begin ...))
PATTERN
# @!method on_numblock_body_of_reduce(node)
def_node_matcher :on_numblock_body_of_reduce, <<~PATTERN
(numblock (send _recv {:reduce :inject} !sym) _argscount $(begin ...))
PATTERN
def parent_block_node(node)
node.each_ancestor(:block).first
end
def parent_numblock_node(node)
node.each_ancestor(:numblock).first
end
end
end
end
end
Version data entries
143 entries across 138 versions & 13 rubygems