11 earlier thoughts
[0 n] is a "function" that, when applied to one of these trees, evaluates to a particular leaf or subtree given by n. This is implemented by lines 12 thru 17 plus 21.
[0 n]
n
20 later thoughts
Keyboard navigation
?
c
g
j
←
k
→
p
s
ctrl + enter
alt + enter
esc