Generating game engine boilerplate

[patrickdown]

I've been following this project with interest. One thing I do is work with C++ and game engines. One thing that a they have in common is boilerplate that a class needs to implement to work in the engine. This is often accomplished with macros and sometimes with custom code generation passes.

In cppfront I could see parts of this being accomplish with custom metafuctions.

MyNode: @godot_class type = {
	this: Node;
	// ...
} 

But there is another part that I'm not sure how the current cppfront would help with the boilerplate. This involves exporting properties/methods to be visible in the editor or scripting language.

Example from Godot that uses template magic and macros.

void VoxelMesh::_bind_methods() {
    ClassDB::bind_method(D_METHOD("set_volume_size", "size"), &VoxelMesh::set_volume_size);
    ClassDB::bind_method(D_METHOD("get_volume_size"), &VoxelMesh::get_volume_size);
    ADD_PROPERTY(PropertyInfo(Variant::VECTOR3I, "volume_size", godot::PROPERTY_HINT_NONE), "set_volume_size", "get_volume_size");
    // ...
}

It would be nice if the @godot_class metafunction could build the _bind_methods for you but how does it identify the methods?

Custom attributes that could be queried by the metafunction?

[godot_export] set_volume_size: (size : Vector3i) = {}

A tagging though the method name where the name is rewritten? 😱

gmethod_set_volume_size: (size : Vector3i) = {}

[MaxSagebaum]

From the error messages in the code Herb wants to make metafunctions available on nearly everything.

cppfront/source/parse.h

Line 8050 in 2d9382d

"(temporary alpha limitation) metafunctions are currently not supported on objects, only on types"

So it would be possible to write:

MyNode: @godot_class type = {
	this: Node;
       
        volume_size: @godot_property VECTOR3I = {};
}

[JohelEGP]

Even with only a type metafunction, you can use an alias for std::type_identity_t named godot_property that @godot_class can observe.

[patrickdown]

This seems like a good short term solution thanks,