Elixir vs Ruby (pattern matching vs conditional logic)

example.ex

# elixir
defmodule Example do
  def work(_msg) do
    IO.puts "called 1st function"
  end

  def work(_msg, data=[_a, _b, _c]) do
    IO.puts "called 2nd function #{inspect data}"
  end

  def work(_msg, data=[a, b, _c, _d]) when is_integer(a) and is_list(b) and a > 5 do
    IO.puts "called 3rd function #{inspect data}"
  end

  def work(_msg, data=[_a, _b, _c, _d]) do
    IO.puts "called 4th function #{inspect data}"
  end
end

Example.work("ok")                               # calls first function
Example.work("ok", [:a, :b, :c])                 # calls second function
Example.work("ok", [6, [:i_am_a_list], 11, 12])  # calls third function. 'a' is an integer greater than six, 'b' is a list.
Example.work("ok", [:a, 42, 99, "hello, world"]) # calls fourth function.

example.rb

# to get the same output from the same data in Ruby
class Example
  attr_reader :msg, :data

  def initialize(msg, data = nil)
    @msg  = msg
    @data = data
  end

  def work
    if data
      if data.length == 3
        puts "called 2nd function #{data}"
      elsif data[0].kind_of?(Integer) && data[0] > 5 && data[1].kind_of?(Array)
        puts "called 3rd function #{data}"
      else
        puts "called 4th function #{data}"
      end
    else
      puts "called first function"
    end
  end
end

Example.new("ok").work
Example.new("ok", [:a, :b, :c]).work
Example.new("ok", [6, [:i_am_a_list], 11, 12]).work
Example.new("ok", [:a, 42, 99, "hello, world"]).work