A dude was arguing on CBC a few weeks ago that pizza is a sandwich.
Bread dough. Savoury. Nutritionally complete.
Those are the criteria that in Drew Brown's view, make pizza a sandwich.
"It's a long and convoluted and counter-intuitive argument, but ultimately pizza is a type of hot open-faced sandwich, primarily because the base of the pizza is a bread dough. As we reconstructed a taxonomy of sandwiches, pizza qualifies as a hot open-faced sandwich."
http://www.cbc.ca/radio/the180/not-a...s-so-1.4121904
Adding the pineapple, makes it not a sandwich?