List Length Count Property

length of remaining stack [ x, y ] with count count = length of remaining stack y with count (count + 1)

This property says that we can count the length of a list by popping an element off the list and incrementing the count by 1 at the same time. Thus, by the time we pop off all the elements from a list, we have the full count.

Examples

length of remaining stack [ A, [ "B", [ "C", [ ] ] ] ] with count 0 = length of remaining stack [ "B", [ "C", [ ] ] ] with count (0 + 1)

length of remaining stack [ 2, [ 4, [ 8, [ ] ] ] ] with count 1 = length of remaining stack [ 4, [ 8, [ ] ] ] with count (1 + 1)

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