Does “+p” (or “-p”) in a plan body cause two effects, i.e. updating the belief base and generating the events “+p” (or “-p”)?
Yes, it causes both effects. Note, importantly, that one of the interpreter configuration options allow the user to choose whether the event (if it is by chance relevant to any plans the agent has) will be treated as internal (pushed on top of that same intention) or external (a new intention – i.e., a new “focus of attention” – is created).
