No. Persistent Data Structures are not mutable. The memory space of an older version is not rewritten, it is referenced by the newer version as a part of its definition. ie via composition. It can only safely do this if the data it references is guaranteed to not change.
x = 2 :: 1 :: Nil-- [2, 1]y = 3 :: x -- [3, 2, 1]
In this example both x and y are single linked lists. y is a node with value 3 and a pointer to x. If x was mutable then changing x would change y. That’s bad™ so its not allowed.
No. Persistent Data Structures are not mutable. The memory space of an older version is not rewritten, it is referenced by the newer version as a part of its definition. ie via composition. It can only safely do this if the data it references is guaranteed to not change.
x = 2 :: 1 :: Nil -- [2, 1] y = 3 :: x -- [3, 2, 1]In this example both
xandyare single linked lists.yis a node with value3and a pointer tox. Ifxwas mutable then changingxwould changey. That’s bad™ so its not allowed.If you want to learn more about functional programming I suggest reading Structures and Interpretation of Computer Programs or Learn You a Haskell for Great Good