Directory: Alternative to list_dir_begin: get_files

[nathanfranke]

Describe the project you are working on:
Working on some tests following my recent pull requests on DirAccess bug fixes.

Describe the problem or limitation you are having in your project:
Listing files in a directory requires a lot of boilerplate code.

Example A:

dir.list_dir_begin()

var file = dir.get_next()
while not file.empty():
	print(file)
	file = dir.get_next()

dir.list_dir_end()

Example B:

dir.list_dir_begin()

var file
while true:
	file = dir.get_next()
	if not file:
		break
	print(file)

dir.list_dir_end()

Describe the feature / enhancement and how it helps to overcome the problem or limitation:
This proposal will allow an alternative option that is a lot simpler to write.

Describe how your proposal will work, with code, pseudocode, mockups, and/or diagrams:

for file in dir.list_files():
	print(file)

Note 1: If buffering all the files in a list is an issue, we should probably change file_access_pack

If this enhancement will not be used often, can it be worked around with a few lines of script?:
Technically yes, this can be worked around by writing one of the top examples. However, this is used quite often and will not break compatibility for 3.2.

Note 2: Depending on how people think of this, list_dir_begin, get_next, and list_dir_end could be deprecated or removed in 4.0.

Is there a reason why this should be core and not an add-on in the asset library?:
This is not really relevant since Directory is already part of core.

[Xrayez]

Yeah, I have some code written to work with EditorFileSystemDirectory for editor plugins, including the mentioned get_files method. Similarly you could write get_files_recursive() just like there's make_dir_recursive() and whatnot. But the core functionality will remain simplistic anyways whatever we propose, so I'm for improving the process of traversing the files within a directory using "for loop" at least.

As you can see there, EditorFileSystemDirectory has the methods like get_file_count() and get_file(). At the very least, the Directory class API could be made consistent with EditorFileSystemDirectory on some level.

[nathanfranke]

We could also implement an iterator class for GDScript so there is no buffering issue

[Xrayez]

This sums it up:
https://github.com/bitwes/Gut/blob/d3bd016a4cff8905d44f90a4ad9e21fad30773cb/addons/gut/gut.gd#L861-L863

[nathanfranke]

"git gut" :P

[KoBeWi]

I looked at DirAccess code and the funny thing is that it already stores internally the list of files/directories and get_next() just pops elements from this list xd

EDIT:
Ok, nevermind. I actually looked at one of the implementations. The method is abstract.