defmodule Foo do

@code1     0xA7
@code2		 0x1F
@codes [@code1, @code2]


  def bar(<<type::signed-8, tail::binary>>), when type in @codes do: IO.inspect "Signed: #{type}"

end


# Both of these equal the same result
<<type::signed-8, tail::binary>> = <<0xA7, 0x00>>;
<<type::unsigned-8, tail::binary>> = <<0xA7, 0x00>>;

# The whey won't this get into the def for bar?
Foo.bar <<0xA7, 0x00>>