(1..10).each {println(it)}

(1..10).each(&method(:puts))

module Enumerable
  def each_ie(&block)
    return to_enum(__method__) { each.size } unless block_given?
    each { |e| e.instance_eval(&block) }
  end
end

(1..10).each_ie { puts self }
# 1
# 2
# 3
# 4
# 5
# 6
# 7
# 8
# 9
# 10
#=> 1..10

class Enumerator
  def with_ie(&block)
    return to_enum(__method__) { each.size } unless block_given?
    each { |e| e.instance_eval(&block) }
  end
end

(1..10).map.with_ie { self * self }
#=> [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
(-5..5).select.with_ie { positive? }
#=> [1, 2, 3, 4, 5]

people.map.with_ie { "#{id}: #{first_name} - #{last_name}" }

{a: 1, b: 2}.map.with_ie { self }
#=> [[:a, 1], [:b, 2]]
{a: 1, b: 2}.map.with_ie { self[0] }
#=> [:a, :b]