I would say that a book musical (Oklahoma, The Sound of
Music) is the old-style standard. It does have scenes of
dialogue between songs, and both the songs and the
scenes add significantly to the plot.

Plays like Joseph and the Amazing Technicolor Dreamcoat
have virtually no spoken dialogue - almost everything is
sung. That is becoming the new standard for musicals. I
would put A Little Night Music in the same category - most
of the dialogue (as I recall) is sung, but songs further the
plot. These might be called operettas.

As for revues, I would put shows like Forever Plaid in that
category - the songs do little to further the plot, and
the plot is mostly there to fill time between songs.

Lu "not sure she was actually helpful" isa