Created
January 30, 2015 03:27
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Macro fun in Elixir mimicking Ruby's attr_accessor
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defmodule MacroExp do | |
defmacro attr_accessor(atom) do | |
getter = String.to_atom("get_#{atom}") | |
setter = String.to_atom("set_#{atom}") | |
quote do | |
def unquote(getter)(data) do | |
data |> Map.from_struct |> Map.get(unquote(atom)) | |
end | |
def unquote(setter)(data, value) do | |
data |> Map.put(unquote(atom), value) | |
end | |
end | |
end | |
defmacro attr_reader(atom) do | |
getter = String.to_atom("get_#{atom}") | |
quote do | |
def unquote(getter)(data) do | |
data |> Map.from_struct |> Map.get(unquote(atom)) | |
end | |
end | |
end | |
end | |
defmodule Calculation do | |
import MacroExp | |
defstruct first: nil, second: nil, operator: :plus | |
attr_accessor :first # defines set_first/2 and get_first/1 | |
attr_accessor :second # defines set_second/2 and get_second/1 | |
attr_reader :operator # defines set_operator/2 and get_operator/1 | |
def result(%Calculation{first: first, second: second, operator: :plus}) do | |
first + second | |
end | |
end |
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