this = _level0
x = 1
_x = 0
xx = 100
_level0.xx = undefined
this = _level0
a.x = 2
a._x = 20
xx = 100
b.x = 3
a/b:_x = 30
in function
x = 4
_x = 0
xx = 100
x = 4
b._x = 30
end
