Contrived example to show a use of Proc

useless_number_classify.rb

# frozen_string_literal: true

def useless_number_classify(number)
  if number == 5
    [:five, number]
  elsif number.odd?
    [:odd, number]
  elsif number.even?
    [:even, number]
  end
end

p useless_number_classify(5)
p useless_number_classify(4)
p useless_number_classify(111)

def useless_number_classify_with_proc(number)
  check_five = proc do |n|
    return [:five, n] if n == 5
  end

  check_odd = proc do |n|
    return [:odd, n] if n.odd?
  end

  check_even = proc do |n|
    return [:even, n] if n.even?
  end

  check_five.(number)
  check_odd.(number)
  check_even.(number)
end

p useless_number_classify_with_proc(5)
p useless_number_classify_with_proc(4)
p useless_number_classify_with_proc(111)

We’re definitely in the darker corners of Ruby at this point!