see_stack == good_viewer_location open_stack
see_resources == list_resources good_viewer_location open_viewer
open_resource_at_good_location == good_viewer_location open_resource
see_log == "log.txt" open_resource_at_good_location
see_definitions == "definitions.txt" open_resource_at_good_location
round_to_cents == 100 * ++ floor 100 /
reset_log == "del log.lines[1:] ; log.at_line = 0" evaluate
see_menu == "menu.txt" good_viewer_location open_resource

# Ordered Binary Tree datastructure functions.
BTree-new == swap [[] []] cons cons
 _BTree-P == over [popop popop first] nullary
 _BTree-T> == [cons cons dipdd] cons cons cons infra
 _BTree-T< == [cons cons dipd] cons cons cons infra
 _BTree-E == pop swap roll< rest rest cons cons
 _BTree-recur == _BTree-P [_BTree-T>] [_BTree-E] [_BTree-T<] cmp
BTree-add == [popop not] [[pop] dipd BTree-new] [] [_BTree-recur] genrec