garbage-collection

• roots are the objects which can be referenced directly without going through some other objects.

a = "hello wordl" # root
 
def fun():
    b = "something" # not root. It is referenced through fun
    return lambda : b + 2

• Garbage collection algorithms
  • mark and sweep. Algorithm implemented for lisp language.
    • Mark the object that can be referenced. Start from the roots.
    • Once all marked, clean the objects which are non marked. this is called sweeping.