some more experiments on left recursion

find many interesting results.

a simplest algorithm is get: just one layer while loop, until no different between two memorized value.
but have some problem: how can I control the process?
try to remove memo in rules and automatic compute, but failed.

try to remove memo in rules and automatic compute, but failed.
find some interesting Phenomenon
left recursive is more complex than you imagine forever!
a simple, compromising solution arises, I think it will be OK.