Godot: Expose double linked list to script

Created on 26 Nov 2016  路  3Comments  路  Source: godotengine/godot

There is a double linked list in godots source code (core/list.h).
It would be nice if that would be exposed as there are some cases where a double linked list performs way better as a vector based.
Especially when it comes to inserting/removing elements at any position except the end.

I could do some work on this, but am not sure how to handle locking and registering it (Although i could try to mirror the behavior of the Array class).
Basically exposing the list and list::Element should do the trick i guess .?
Implementing it as iterable should also work similar to how Array does it.

Additionally (and if requested i could open another issue for this) exposing the core/ring_buffer.h as queue would also be nice for queue needs.
It should perform better as a queue using a double linked list (and def. better as a vector based list) with the limitation that it has a "fixed" size and potential allocates unused memory ofc.
But there are cases where exactly this behavior is needed.

archived feature proposal core gdscript

Most helpful comment

Still reproducible/relevant in 3.1 master 9e7cee2 : such data stucture isn't exposed yet.

All 3 comments

Still reproducible/relevant in 3.1 master 9e7cee2 : such data stucture isn't exposed yet.

Was about to post on reddit asking if there's a proper linked-list implementation I can use.

I need a fast FIFO list, and array isn't doing the job.

Just wrote this as an array replacement, and got significant speed improvements:

extends Node

var front_space = 0
var array_len = 0
var array_data = []

func push_back(val):
    if array_data.size() < front_space+array_len+1:
        enlarge()
    array_len += 1
    array_data[front_space+array_len-1] = val

func pop_back():
    if array_data.size() > array_len*8:
        reseat()
    array_len -= 1
    return array_data[front_space+array_len]

func back():
    return array_data[front_space+array_len-1]

func pop_front():
    if front_space > array_len:
        reseat()
    if array_data.size() > array_len*8:
        reseat()
    front_space += 1
    array_len -= 1
    return array_data[front_space-1]

func front():
    return array_data[front_space]

func size():
    return array_len

func enlarge():
    array_data.resize(front_space+array_len*2+1)

func reseat():
    var new_array = []
    new_array.resize(array_len*2)
    for i in range(array_len):
        new_array[i] = array_data[i+front_space]
    front_space = 0
    array_data = new_array

func print_debug():
    print("front: ", front_space,", len: ",arr

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