An example Enumerable ARGV/STDIN for #ruby IRC

words.rb

Words = Data.define(:argv, :stdin)
class Words
  STDIN_ARGV = ["-"].freeze

  include Enumerable

  def initialize(argv: ARGV, stdin: $stdin) = super

  def each(&)
    return enum_for(__method__) unless block_given?
    return argv.each(&) unless argv == STDIN_ARGV

    stdin.each_line.lazy.flat_map(&:split).each(&)
  end
end

Words.new(ARGV).each { |word| # ...