Elixir currying

currying.ex

defmodule Currying do
  def function ~> argument when is_function(function) do
    curry(function, argument)
  end
  
  def curry(function, arguments) when is_function(function) and is_list(arguments) do
    {:arity, arity} = Function.info(function, :arity)
    
    arguments = Enum.reverse(arguments)
    
    do_curry(function, arity, arguments)
  end
  
  def curry(function, argument) when is_function(function) do
    curry(function, [argument])
  end
  
  def curry(function) when is_function(function) do
    curry(function, [])
  end
  
  defp do_curry(function, arity, arguments) when length(arguments) > arity do
    raise BadArityError, function: function, args: arguments
  end
  
  defp do_curry(function, arity, arguments) when length(arguments) < arity do
    fn argument ->
      do_curry(function, arity, [argument | arguments])
    end
  end
  
  defp do_curry(function, arity, arguments) when length(arguments) == arity do
    arguments = Enum.reverse(arguments)
    
    apply(function, arguments)
  end
end

import Currying

test = fn a, b, c -> {a, b, c} end

curry(test).(1).(2).(3)

curry(test, [1]).(2).(3)

curry(test, [1, 2]).(3)

curry(test, [1, 2, 3])

curry(test, [1, 2, 3, 4])

(test ~> 1).(2).(3)