[Reflection] Getting struct field names and types without a world or entity

[nicklongdesign]

I'm looking into ways to edit a scene in a graphical space and currently considering two options:

1. Make a Blender add-on or extend https://github.com/sdfgeoff/blender_bevy_toolkit to suit our needs
2. Make an "editor mode" in our game that can save out to scene files

One thing that's necessary to Blender approach is to get a list of all components, the names of their fields and their types. I would very much like to ask the game for this information with a command line argument rather than manually create JSON blobs whenever I create a component. I poked around and experimented with the Reflection module a little bit and found it very easy to a get a list of all the components. What was more challenging was getting the names and types of component fields. The only way I was able to accomplish this was to create a World and an entity, add components to that entity and then use the ReflectComponent to get the more detailed type data.

Is there a way to get field name and types from the TypeRegistry without instantiating a world and an entity that has the components on it? If not, is there a way to say "Make an entity and add one of every component on it"?

[nicopap]

Bevy version 0.8 introduces the TypeInfo struct, which is exactly what you need. It allows you to get a type's field list and info without access to an instance. 0.8 is right around the corner. So I'd say hang in there!