How to call run_system_once_with?

[bbarker]

Say I have a system with function signature:

pub fn get_player_no_ecs(
    query: Query<(Entity, &Name), With<Player>>,
    player_name: impl Into<String>,
) -> Option<Entity> 

Looking at the system piping example, I thought maybe I should do something like this:

pub fn get_player_no_ecs(
    query: Query<(Entity, &Name), With<Player>>,
    In(player_name): In<impl Into<String>>,
) -> Option<Entity> 

However, I'm not sure how to use this with World::run_system_once_with (supposing I have player_name in hand at the call site).

[NiklasEi]

It should "just" be

world.run_system_once_with(player_name, get_player_no_ecs)

are you running into issues with that?

I do something very similar in Cinnog. It looks like run_system_once_with could save me some code there actually 🤔

[bbarker]

I can get past the issue if I remove the string parameter (player_name) entirely - of course I actually need it in the game logic.

Otherwise, I've not been able to figure out why my system fn doesn't satisfy the trait bounds yet:

error[E0277]: the trait bound `for<'a, 'b, 'c> fn(bevy::prelude::Query<'a, 'b, (bevy::prelude::Entity, &'c bevy::prelude::Name), bevy::prelude::With<components::Player>>, bevy::prelude::In<_>) -> std::option::Option<bevy::prelude::Entity> {get_player_no_ecs::<_>}: bevy::prelude::IntoSystem<bevy::prelude::In<impl Into<String>>, _, _>` is not satisfied
   --> src/player.rs:370:47
    |
370 |     ecs.run_system_once_with(In(player_name), get_player_no_ecs)
    |         --------------------                  ^^^^^^^^^^^^^^^^^ the trait `bevy::prelude::IntoSystem<bevy::prelude::In<impl Into<String>>, _, _>` is not implemented for fn item `for<'a, 'b, 'c> fn(bevy::prelude::Query<'a, 'b, (bevy::prelude::Entity, &'c bevy::prelude::Name), bevy::prelude::With<components::Player>>, bevy::prelude::In<_>) -> std::option::Option<bevy::prelude::Entity> {get_player_no_ecs::<_>}`
    |         |
    |         required by a bound introduced by this call
    |
note: required by a bound in `run_system_once_with`
   --> /home/bbarker/.cargo/registry/src/index.crates.io-6f17d22bba15001f/bevy_ecs-0.12.1/src/system/system.rs:265:32
    |
265 | ...m_once_with<T: IntoSystem<In, Out, Marker>, In, Out, Marker>(
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `RunSystemOnce::run_system_once_with`

[NiklasEi]

Is the In parameter the first Parameter of the system?

[bbarker]

ah, that was it! I thought I tried that at some point, but probably not in the right permutation with usage of In