34 lines
822 B
Elixir
34 lines
822 B
Elixir
defmodule RotationalCipher do
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@doc """
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Given a plaintext and amount to shift by, return a rotated string.
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Example:
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iex> RotationalCipher.rotate("Attack at dawn", 13)
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"Nggnpx ng qnja"
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"""
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@next_upper %{A: "B", B: "C", C => "D", D => "E", E => "F", }
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@spec rotate(text :: String.t(), shift :: integer) :: String.t()
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def rotate(text, shift) do
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String.codepoints(text)
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|> Enum.map(fn(x) -> rotate_upper(x, shift) end)
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|> Enum.map(fn(x) -> rotate_lower(x, shift) end)
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|> to_string
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end
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def rotate_upper(text, shift) do
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# map(text, (fn x -> if(is_uppercase(x) do
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# |> IO.chardata_to_string
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# end))
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end
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def is_uppercase(letter) do
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letter =~ ~r/^\p{Lu}$/u
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end
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def rotate_lower(text, shift) do
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String.to_charlist("łł")
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end
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end
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