Contents

defmodule RotationalCipher do
  @alphabet "abcdefghijklmnopqrstuvwxyz"
  @alphabet_size String.length(@alphabet)

  for shift <- 0..25 do
    plain = String.split(@alphabet, "", trim: true)
    cipher = @alphabet
             |> Kernel.<>(@alphabet)
             |> String.split("", trim: true)
             |> Enum.drop(shift)
             |> Enum.take(@alphabet_size)
    for {p, c} <- Enum.zip(plain, cipher) do
      def translate(unquote(p), unquote(shift)), do: unquote(c)
      def translate(unquote(p |> String.upcase), unquote(shift)), do: unquote(c |> String.upcase)
    end
  end

  # Non a-zA-Z just returns the original character
  def translate(plaintext, _), do: plaintext

  @doc """
  Given a plaintext and amount to shift by, return a rotated string.

  Example:
  iex> RotationalCipher.rotate("Attack at dawn", 13)
  "Nggnpx ng qnja"
  """
  @spec rotate(text :: String.t(), shift :: integer) :: String.t()
  def rotate(text, shift) do
    text
    |> String.split("", trim: true)
    |> Enum.map_join(&(translate(&1, shift)))
  end
end

Version data entries

208 entries across 208 versions & 1 rubygems

Version	Path
trackler-2.2.1.109	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.108	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.107	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.106	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.105	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.104	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.103	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.102	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.101	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.100	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.99	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.98	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.97	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.96	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.95	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.94	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.93	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.92	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.91	tracks/elixir/exercises/rotational-cipher/example.exs
trackler-2.2.1.90	tracks/elixir/exercises/rotational-cipher/example.exs