[erlang-questions] call by value

[Martin Dimitrov]

Hi,

How will we have to interpret this citation from "Erlang Programming" by
Francesco Cesarini and Simon Thompson (page 30):

"All calls with variables in Erlang are call by value: all arguments to
a function call are evaluated before the body of the function is
evaluated. The concept of call by reference does not exist, ..."

I know that variables are not copied when making a function call and are
copied when sending messages to processes. So why do the authors say all
calls are call by value? Aren't the function calls actually call by
reference?

Regards,

Martin