RupparUpaka

[Tom Cooper]

I'm researching the history of shadow puppets, and a possible early
documentation occurs in Theri-gatha #394.  The word is "rupparUpaka" and is
translated as "shadow play" [Schattenspiel] in Jacob, but as "puppet show"
in Rhys David and Norman.  Oldenberg & Pischel noted that the exact meaning
is unclear.

Does anyone know of any further scholarship on the word that might shed
light on the question of whether this word should be regarded as a
reference to shadow puppets?