Steve writes '…performs a particular literal and practical function, without need to include any hidden meanings.'
You're right of course Steve, but only in our world. You have to see the song through the eyes and ears of another time. In that and most earlier periods of history the 'hidden meanings' were plain for all and indeed sought out simply because of their clevernesss. Now I suppose you'll want proof of that? Just visit your local Art Gallery and examine any 19th century painting. You'll see a tradition of 'hidden meanings' that goes back further than you can possibly imagine. I have no intention of playing at being a druid but I am an ex-arts teacher and creative artist and can assure you that 'hidden meanings' are something much more widespread and important than you wish to acknowledge.