MultiDef—Define a function with multiple heads

Add the dependency {:multidef, "> 0.0.0"} to mix.exs.

Use it like this:

  defmodule Test do

    import MultiDef

    mdef fib do
      0 -> 0
      1 -> 1
      n -> fib(n-1) + fib(n-1)
    end
  end

  IO.puts Test.fib(20)

When clauses can be used:

  defmodule Test do

    import MultiDef

    mdef fib do
      0 -> 0
      1 -> 1
      n when n > 0 -> fib(n-1) + fib(n-1)
    end
  end

  IO.puts Test.fib(20)

Does not support default arguments.

Does not enforce that all heads have the same arity (deliberately).

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Copyright © 2014 Dave Thomas, The Pragmatic Programmers
@/+pragdave, dave@pragprog.com

Licensed under the same terms as Elixir