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Versions: 86
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Contents
defmodule Atbash do
@key Enum.zip(?a..?z, ?z..?a) |> Enum.into(%{})
@doc """
Encode a given plaintext to the corresponding ciphertext
## Examples
iex> Atbash.encode("completely insecure")
"xlnko vgvob rmhvx fiv"
"""
@spec encode(String.t) :: String.t
def encode(plaintext) do
plaintext |> normalize |> transpose |> chunk |> Enum.join(" ")
end
@spec decode(String.t) :: String.t
def decode(cipher) do
cipher |> normalize |> transpose
end
defp normalize(input) do
Regex.replace(~r{\W}, String.downcase(input), "")
end
defp transpose(text) do
text
|> String.to_char_list
|> Enum.map(&convert/1)
|> List.to_string
end
defp convert(character) do
Map.get(@key, character, character)
end
defp chunk(input) do
Regex.scan(~r(.{1,5}), input) |> List.flatten
end
end
Version data entries
86 entries across 86 versions & 1 rubygems