This function returns the number of environments between env and
the empty environment, including env. The depth of
env is also the number of parents of env (since the empty
environment counts as a parent).
Usage
env_depth(env)
Arguments
env
An environment or an object bundling an environment,
e.g. a formula, quosure or closure.
Value
An integer.
See Also
The section on inheritance in env() documentation.