Programmer Humor

19623 readers

89 users here now

Welcome to Programmer Humor!

This is a place where you can post jokes, memes, humor, etc. related to programming!

For sharing awful code theres also Programming Horror.

Rules

Keep content in english
No advertisements
Posts must be related to programming or programmer topics

founded 1 year ago

MODERATORS

[email protected]

394

You wouldn’t get it (sh.itjust.works)

submitted 7 months ago by [email protected] to c/[email protected]

44 comments fedilink hide all child comments

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 2 points 7 months ago

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.

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