I've been wanting this feature for a bit. This will be great to have.

find_custom is a 4.4 feature and GUT requires 4.3 (also I'm using 4.3 still). I don't think this is a big enough feature to require 4.4 but I understand not wanting to work in 4.3. So, please either:

• Change the implementation to work in Godot 4.3
  or
• Make the PR against the Godot 4.4 branch.

Oh dear silly me. Probably should've thought about that first. Here's a fixed version for 4.3.

Sorry for the delay. I checked this out a bit then got distracted with Godotcon. This works, but I think I would like the following changes:

• Change the handling of op_name in the add function to handle a string value or an array.
• When it is a string, you get a an option without an aliases.
• When it is an array, then every value after the first is an alias.

This allows us to keep all the option names together which is easier to read. In my experience it is rare that you would want more than one alias for an option (I can't think of an example off the top of my head). By putting the optional array at the front, we can still support more aliases but don't have to use a single element array in usual use case.

This would change the usage to something like:

op.add("--name", "default", "description")
op.add(["--name", "-n"], "default", "description")
op.add(["--name", "--nombre", "--namna", "-n"], "default", "description")

Okay, it's been updated to have the specified behavior. I also added type hints and docstrings to all the user facing methods and rebuilt the class reference docs for them.

This looks good. Thanks a lot for adding this.