Also, adding an "catch all" is usually not recommended in Erlang (even though it's good for some things), so most of the time you would do just: foo(bar) -> voi

Also, adding an "catch all" is usually not recommended in Erlang (even though it's good for some things), so most of the time you would do just: foo(bar) -> void. And then let it crash if the value is something else than expected.