this post was submitted on 15 Apr 2024
397 points (91.6% liked)
Programmer Humor
19552 readers
1100 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
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
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.
In this example both
x
andy
are single linked lists.y
is a node with value3
and a pointer tox
. Ifx
was mutable then changingx
would 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