Add with_cloned_input and WithClonedInputWrapper to system functionality

[pantaelaman]

Objective

I didn't see an issue for something like this made yet, but I ran into a particularly non-ergonomic situation when working on a prototype where I wanted to be able to run a system that normally takes owned input via In with a static, cloneable value. The with_input and with_input_from functions both require the system takes a mutable reference to their input types, so they wouldn't work for my general case.

Solution

I effectively copied the code from the WithInputWrapper and WithInputFromWrapper structs and modified it slightly so that it clones the contained value and passes it as input to the wrapped system.

Testing

The project successfully builds on my machine, and my personal game prototype was built and ran successfully using this extra functionality. Totally possible I missed an edge case though.

---

Showcase

struct GridCoord {
  location: IVec2,
}

fn spawn_creature(In(location): In<IVec2>, mut commands: Commands) {
  commands.spawn((
    GridCoord { location },
    // some other stuff too...
  ))

  // and maybe some other stuff here...
}

struct CreaturePlugin;

impl Plugin for CreaturePlugin {
  fn build(app: &mut App) {
    app.add_systems(Startup, spawn_creature.with_cloned_input(IVec2::new(0, 0));
  }
}

The idea being that I want to use spawn_creature somewhere else with dynamic input, using run_system_cached_with, but on some schedule (in this case, Startup), I want to give it a constant input.

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