edf50fdf80
- Run mix credo --all to identify possible code optimizations - Resolve most of the errors generated by credo such as: - Numbers larger than 9999 should be written with underscores: 58_127 - Modules should have a @moduledoc tag - Comparison will always return true
65 lines
1.4 KiB
Elixir
65 lines
1.4 KiB
Elixir
defmodule Protocols do
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@moduledoc false
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use Koans
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@intro "Want to follow the rules? Adhere to the protocol!"
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defprotocol(Artist, do: def(perform(artist)))
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defimpl Artist, for: Any do
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def perform(_) do
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"Artist showed performance"
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end
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end
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defmodule Painter do
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@moduledoc false
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@derive Artist
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defstruct name: ""
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end
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defmodule Musician do
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@moduledoc false
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defstruct(name: "", instrument: "")
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end
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defmodule Dancer do
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@moduledoc false
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defstruct(name: "", dance_style: "")
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end
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defmodule Physicist do
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@moduledoc false
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defstruct(name: "")
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end
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defimpl Artist, for: Musician do
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def perform(musician) do
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"#{musician.name} played #{musician.instrument}"
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end
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end
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defimpl Artist, for: Dancer do
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def perform(dancer), do: "#{dancer.name} performed #{dancer.dance_style}"
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end
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koan "Sharing an interface is the secret at school" do
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musician = %Musician{name: "Andre", instrument: "violin"}
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dancer = %Dancer{name: "Darcy", dance_style: "ballet"}
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assert Artist.perform(musician) == ___
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assert Artist.perform(dancer) == ___
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end
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koan "Sometimes we all use the same" do
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painter = %Painter{name: "Emily"}
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assert Artist.perform(painter) == ___
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end
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koan "If you are not an artist, you can't show performance" do
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assert_raise ___, fn ->
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Artist.perform(%Physicist{name: "Delia"})
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end
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end
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end
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