Macro for testings pattern and guards in iex.

pattern_match.ex

# Put in your .iex, and `require Pattern`
defmodule Pattern do
  defmacro match?(pattern, input, code_block // []) do
    code = Dict.get(code_block, :do, nil)
    quote do
      case unquote(input) do
        unquote(pattern) ->
          unquote(code)
          :ok
        _ ->
          :no_match
      end
    end
  end
end
# Pattern.match? [1, x, y], [1, 2, 3]
#=> :ok
# Pattern.match? [1, x, y], [2, 2, 3]
#=> :no_match
# Pattern.match? [1, x, y], [1, 2, 3], do: x |> inspect |> IO.puts
#==> 2
#=> :ok
# Pattern.match? x when x < 10, 10, do: x |> inspect |> IO.puts
#=> :no_match
# Pattern.match? x when x >= 10, 10, do: x |> inspect |> IO.puts
#==> 10
#=> :ok