Each time we execute a statement in an
iex session, the counter is
incremented. These numbers are references to the history of the session. We
can use these references to refer to previously executed values using
v/1. This is particularly handy for multi-line statements or when we
forget to bind to the result of some function.
Consider the following
iex(1)> :one :one iex(2)> 1 + 1 2 iex(3)> "three" |> String.to_atom() :three
If we execute
v() on its own, it is the same as
v(-1) in that it will
give us the latest value in the history.
iex(4)> v() :three
Providing any positive number will refer to the references we see next to each statement.
iex(5)> v(1) :one
Negative numbers, as we saw with
v(-1), will count backwards in the
history from where we are.
iex(6)> v(-4) 2
h v for more details.