pub fn invoke(helper: &mut Program, action: &Action) -> Result
Expand description
Invoke the given helper
with action
in context
.
Usually the first call is performed with Action::Get
to obtain Some
identity, which subsequently can be used if it is complete.
Note that it may also only contain the username or password, and should start out with everything the helper needs.
On successful usage, use NextAction::store()
, otherwise NextAction::erase()
, which is when this function
returns Ok(None)
as no outcome is expected.