[danielnesbitt]

Pure functional languages often do not use the same data structures common in imperative languages. Instead there's an emphasis on persistent structures that copy on write while sharing as much data as possible.

For instance, prepending to a linked list results in a new head node, but nothing is actually copied. Appending requires a full copy. A developer has to be aware of where the limitations of these data structures are, but I think that's true of using any library in any language.

https://en.wikipedia.org/wiki/Persistent_data_structure

[mohaine]

The performance issue still stands. Linked Lists are often MUCH slower then array backed lists on modern hardware. This is true even when doing lots of inserts. Having all your list in the CPU cache is just too much of a performance gain over having it spread out in random locations.

[whateveracct]

Depending on your GC, linked lists won't be "spread out in random locations." The nodes will be allocated right next to each other in the case where you're building up a list iteratively.

[mohaine]

How does the GC change allocations?

While I agree that this Linked list memory layout should be optimized, with real world tests Array backed normally win by a large margin.