Add a simpler way to get string values from enums

[bojidar-bg]

Godot version:
Godot 3.1

Issue description:
Currently, getting a String from a GDScript enum value is hard, and requires either a separate mapping dictionary/array. Ideally, there should be a way to get the key of any enum (script or otherwise), for easy debugging and potential use in UIs.

Some ideas:

• Add Dictionary.reverse() which turns {a: b, c: d} into {b: a, d: c}, likely erroring on duplicates. This would remove the need for a separate mapping.
• Add reverse entries to the enum dictionary, turning {"enum_key": 4} into {"enum_key": 4, 4: "enum_key"}. This would break backwards compatibility, and turns enums into a bigger pile of hacks.
• Add Variant::Enum which contains both an int and a StringName. It would be implicitly casted to both strings and ints, so printing an enum value would automatically print its name. Adding more types to Variant is not cheap though.

[TheFlamyy]

Generally speaking I'd prefer something like Dictionary.find_key(value). Technically it could go hand in hand with a reverse method. It would have a general use case besides enums.

I quickly created a GDScript equivalent:

func find_key(dictionary, value):
	var index = dictionary.values().find(value)
	return dictionary.keys()[index]

[Reneator]

Maybe this is already known, but just want to add my bit:

Im currently trying to use Enum-Values for my resources/nodes, as export variables (to have them as options for easy setup and consistency throughout the code)

But with the current concept, if i save the variables to a file, i would just save the int of the enums (position in the enum-"dict"). So when i change the order of any enum, I would destroy the compatabilty of saves.

So here its either: build a workaround solution or use strings directly instead of enums.

I personally would prefer if it would be able to just have the direct information of string <-> enum (but as optional possibility). Akin to java's handling of enums.

Edit: This also affects "export (ENUM)" fields of resources, as they also only save the int-value and not the enum per se (or a string to which the enum may be directly linked)

[KoBeWi]

Is this about retrieving value keys for Enums, like this?
var key = enum.keys()[enum.keys().find(value)]

[PLyczkowski]

Also check out godotengine/godot-proposals#255 since it addresses a similar problem.

[mhilbrunner]

Superseded godotengine/godot-proposals#255 - or consider creating a new proposal if that one doesn't fit completely, as proposals are now moved to that repository :)