zuse: add backward tap (+bap) to +ordered-map
?~ a b
::
$(a l.a, b [n.a $(a r.a)])
+ :: +bap: convert to list, largest to smallest
+ ::
+ ++ bap
+ |= a=(tree item)
+ ^- (list item)
+ ::
+ =| b=(list item)
+ |- ^+ b
+ ?~ a b
+ ::
+ $(a r.a, b [n.a $(a l.a)])
:: +gas: put a list of items
::
++ gas
