gistfile1.md

Trivial Example: Compose a meet & greet in Ruby

class Greeter
  class << self
    def meet(person, &block)
      yield person
    end

    # Greet everyone except Johnny
    def greet(person, &block)
      if person == "Johnny"
        yield "Can't talk right now, Johnny"
      else
        yield "Hello #{person}!"
      end
    end
  end
end

Greeter.meet "Johnny" do |person|
  Greeter.greet person do |message|
    puts message
  end
end

Greeter.meet "Brooke" do |person|
  Greeter.greet person do |message|
    puts message
  end
end

The same functionality in Elixir:

defmodule Greeter do
  def meet(person), do: person
  
  def greet("Johnny"), do: "Can't talk right now, Johnny"
  def greet(person), do: "Hello #{person}!"
end

"Johnny" |> Greeter.meet |> Greeter.greet |> IO.puts
"Brooke" |> Greeter.meet |> Greeter.greet |> IO.puts

As a fan of both Ruby and Elixir, what you have is interesting but not quite equivalent and is therefore not quite fair to Ruby.

This is because I am noticing that you are defining blocks in Ruby that you aren't using. Hence, it seems as the equivalent Ruby to what you're doing in Elixir would look like:

class Greeter
  class << self
    def meet(person) person end
    def greet(person) person == 'Johnny' ? "Can't talk right now, Johnny" : "Hello #{person}!" end
  end
end

puts(Greeter.greet Greeter.meet('Johnny')) # => "Can't talk right now, Johnny"
puts(Greeter.greet Greeter.meet('Brooke')) # => "Hello Brooke!"

So you can see the that LOC for the two versions are much closer together.

That being said, you do gain efficiency with Elixir's pattern matching, and I do like the |> syntax in Elixir.

@oldfartdeveloper my example is contrived to show composition. I wasn't trying to make the Ruby look like Elixir as much as follow the composition. I could argue to that most Rubyist would write that code a little differently, especially once more data transformation was needed. The problem with trivial examples are there are a number of ways to solve the problem but the one you use depends on what you are trying to show.

I see both sides, but think both are idiomatic of their implementing language and is a fair comparison. Also to consider, less lines of code does not mean better. Though I do think the Elixir example is just as, if not more, readable as the Ruby so it "wins" on both fronts.