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Contents
# encoding: utf-8
module RuboCop
module Cop
module Style
# This cop checks for places where Fixnum#even? or Fixnum#odd?
# should have been used.
#
# @example
#
# # bad
# if x % 2 == 0
#
# # good
# if x.even?
class EvenOdd < Cop
MSG_EVEN = 'Replace with `Fixnum#even?`.'
MSG_ODD = 'Replace with `Fixnum#odd?`.'
ZERO = s(:int, 0)
ONE = s(:int, 1)
TWO = s(:int, 2)
def on_send(node)
receiver, method, args = *node
return unless [:==, :!=].include?(method)
return unless div_by_2?(receiver)
if args == ZERO
add_offense(node,
:expression,
method == :== ? MSG_EVEN : MSG_ODD)
elsif args == ONE
add_offense(node,
:expression,
method == :== ? MSG_ODD : MSG_EVEN)
end
end
private
def div_by_2?(node)
return unless node
# check for scenarios like (x % 2) == 0
if node.type == :begin && node.children.size == 1
node = node.children.first
end
return unless node.type == :send
_receiver, method, args = *node
method == :% && args == TWO
end
end
end
end
end
Version data entries
11 entries across 11 versions & 2 rubygems