  We introduce AVAR, a prototypical implementation of an agile situated
visualization (SV) toolkit targeting liveness, integration, and expressiveness.
We report on results of an exploratory study with AVAR and seven expert users.
In it, participants wore a Microsoft HoloLens device and used a Bluetooth
keyboard to program a visualization script for a given dataset. To support our
analysis, we (i) video recorded sessions, (ii) tracked users' interactions, and
(iii) collected data of participants' impressions. Our prototype confirms that
agile SV is feasible. That is, liveness boosted participants' engagement when
programming an SV, and so, the sessions were highly interactive and
participants were willing to spend much time using our toolkit (i.e., median >=
1.5 hours). Participants used our integrated toolkit to deal with data
transformations, visual mappings, and view transformations without leaving the
immersive environment. Finally, participants benefited from our expressive
toolkit and employed multiple of the available features when programming an SV.
