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Lets you define multiple heads for the same function: defmodule Test do import MultiDef mdef fred do { :init, val } -> fred {:double, val} { :double, val } -> IO.puts(val*2) a, b -> a+b end end IO.inspect Test.fred 1, 2 ...

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README.md

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