Add additional macros

[alicerunsonfedora]

I'm introducing the macro library from Indexing Your Heart's source upstream since I think they will benefit developers using this package to create scripts for Godot:

• @NativeHandleDiscarding is a macro that initializes init(nativeHandle:) for you. This isn't meant to supersede the existing @Godot macro, but it can be used if developers prefer to do things manually.
• #initSwiftExtension is a macro for quickly setting up an extension by writing the entrypoint methods for you, only requiring the C name and the array of types to be registered with the Godot engine.
• #texture2DLiteral is a macro for quickly fetching an image resource and using it as a texture.
• @PickerNameProvider is a macro for giving an enum the backing and conformances needed to register them in Godot.
• @SceneTree is a macro that adds a get accessor to properties, referencing the scene tree. Consider this a replacement of the existing @BindNode property wrapper.

I've also updated the tutorials to utilize the new macros.

Note
Indexing Your Heart is licensed under the CNPLv7, and these macros were a part of that in a separate package. However, because I am the sole author of the game at the moment with no contributors, I have the authority to have them relicensed under SwiftGodot's existing license. I also highly doubt they can be used to harm someone directly.

[PadraigK]

Just curious, is there a way to see this "Texture could not be loaded." text when the game hits it? Any fatalError / preconditionFailures I've tried just leads to a crash in godot, and even the crash doesn't seem to show the actual failure text.

[alicerunsonfedora]

Not to my knowledge, but I could call a GD.pushError beforehand so that the error is present in the Godot console before the crash.

[PadraigK]

Thanks for getting back to me! I just tried this and the error doesn't make it to the Godot console unfortunately. No worries anyway, this is not a reason to change the PR, which is really cool overall! Thanks for sharing it.

[alicerunsonfedora]

Ah, I guess it must happen so quickly that Godot doesn't even have the chance to report the error. Though I wonder if it appears in the stacktrace or logs.

[alicerunsonfedora]

Appears this might require a flag of some kind:

message.
A string to print in a playground or -Onone build. The default is an empty string.

https://developer.apple.com/documentation/swift/preconditionfailure(_:file:line:)

[PadraigK]

A debug build should be -Onone already, I suspect it's dying before the logs are flushed. I'll open a separate issue to discuss this.

[PadraigK]

Opened #132 to discuss.

[alicerunsonfedora]

@PadraigK Perhaps you can try replacing my GD.pushError with Swift's default print and see if you get something in the terminal?

[PadraigK]

To get this working in my project, I had to add .product(name: "SwiftGodotMacros", package: "SwiftGodot") to my .target dependencies. It would be good to add this to the tutorial where it describes the setup of the driver package.

[migueldeicaza]

I am still a bit concerned that we have duplicate functionality now, and would rather only have one way of doing things.

I am ok taking this over my existing solution, but we should at least make this default the path to being the name of the variable, so users do not have to repeat themselves, something like:

@SceneTree var myTimer: Timer

Should infer that the name of the timer in the scene is myTimer