I'm working through Sasa Juric's "Elixir In Action" and I spotted something I find a little bit puzzling. I was working through the examples he gives around page 140 or so and I saw this:
iex(2)> send(self, {:message, 1}) # Line 1
{:message, 1}
iex(3)> receive_result = receive do
...(3)> {:message, x} -> x + 2
...(3)> end
3
iex(4)> IO.inspect receive_result
3
3
Why does IO.inspect print the value twice? Is it related to the send message on Line 1 immediately displaying the tuple?
This is just how IO.inspect/2 works in iex:
iex(10)> IO.inspect(3)
3 # From IO.inspect
3 # return value in iex
This happens since IO.inspect prints the value and returns the same value. IO.puts/2 prints the value and returns :ok
iex(11)> IO.puts(3)
3 # From IO.puts
:ok # return value in iex