Struct OnceFunctionSystem 

pub struct OnceFunctionSystem<F, Marker, State = ()> { /* private fields */ }

Type-erased wrapper produced by OnceExt::once. Runs func every time it’s invoked until func returns Some(()), at which point it’s permanently retired — every subsequent invocation (and requirement check) is a no-op. The “have I already succeeded” bookkeeping lives entirely in done, hidden inside this wrapper; the wrapped function itself just returns None (“not ready, call me again”) or Some(()) (“done”).

Trait Implementations

impl<T> IntoSystem<()> for OnceFunctionSystem<T, (), ()>

where T: for<'a> FnMut() -> Option<()> + 'static,

type System = OnceFunctionSystem<T, ()>

fn into_system(self) -> Self::System

impl<T, A, B> IntoSystem<(A, B)> for OnceFunctionSystem<T, (A, B), (A::State, B::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B), (<A as SystemParam>::State, <B as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C> IntoSystem<(A, B, C)> for OnceFunctionSystem<T, (A, B, C), (A::State, B::State, C::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C, D> IntoSystem<(A, B, C, D)> for OnceFunctionSystem<T, (A, B, C, D), (A::State, B::State, C::State, D::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C, D), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State, <D as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C, D, E> IntoSystem<(A, B, C, D, E)> for OnceFunctionSystem<T, (A, B, C, D, E), (A::State, B::State, C::State, D::State, E::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C, D, E), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State, <D as SystemParam>::State, <E as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C, D, E, F> IntoSystem<(A, B, C, D, E, F)> for OnceFunctionSystem<T, (A, B, C, D, E, F), (A::State, B::State, C::State, D::State, E::State, F::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C, D, E, F), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State, <D as SystemParam>::State, <E as SystemParam>::State, <F as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C, D, E, F, G> IntoSystem<(A, B, C, D, E, F, G)> for OnceFunctionSystem<T, (A, B, C, D, E, F, G), (A::State, B::State, C::State, D::State, E::State, F::State, G::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C, D, E, F, G), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State, <D as SystemParam>::State, <E as SystemParam>::State, <F as SystemParam>::State, <G as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C, D, E, F, G, H> IntoSystem<(A, B, C, D, E, F, G, H)> for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C, D, E, F, G, H), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State, <D as SystemParam>::State, <E as SystemParam>::State, <F as SystemParam>::State, <G as SystemParam>::State, <H as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C, D, E, F, G, H, I> IntoSystem<(A, B, C, D, E, F, G, H, I)> for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State, I::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>, I::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static, I: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State, <D as SystemParam>::State, <E as SystemParam>::State, <F as SystemParam>::State, <G as SystemParam>::State, <H as SystemParam>::State, <I as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C, D, E, F, G, H, I, J> IntoSystem<(A, B, C, D, E, F, G, H, I, J)> for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I, J), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State, I::State, J::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>, I::Item<'a>, J::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static, I: SystemParam + 'static, J: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I, J), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State, <D as SystemParam>::State, <E as SystemParam>::State, <F as SystemParam>::State, <G as SystemParam>::State, <H as SystemParam>::State, <I as SystemParam>::State, <J as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C, D, E, F, G, H, I, J, K> IntoSystem<(A, B, C, D, E, F, G, H, I, J, K)> for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I, J, K), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State, I::State, J::State, K::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>, I::Item<'a>, J::Item<'a>, K::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static, I: SystemParam + 'static, J: SystemParam + 'static, K: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I, J, K), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State, <D as SystemParam>::State, <E as SystemParam>::State, <F as SystemParam>::State, <G as SystemParam>::State, <H as SystemParam>::State, <I as SystemParam>::State, <J as SystemParam>::State, <K as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A, B, C, D, E, F, G, H, I, J, K, L> IntoSystem<(A, B, C, D, E, F, G, H, I, J, K, L)> for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I, J, K, L), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State, I::State, J::State, K::State, L::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>, I::Item<'a>, J::Item<'a>, K::Item<'a>, L::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static, I: SystemParam + 'static, J: SystemParam + 'static, K: SystemParam + 'static, L: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I, J, K, L), (<A as SystemParam>::State, <B as SystemParam>::State, <C as SystemParam>::State, <D as SystemParam>::State, <E as SystemParam>::State, <F as SystemParam>::State, <G as SystemParam>::State, <H as SystemParam>::State, <I as SystemParam>::State, <J as SystemParam>::State, <K as SystemParam>::State, <L as SystemParam>::State)>

fn into_system(self) -> Self::System

impl<T, A> IntoSystem<(A,)> for OnceFunctionSystem<T, (A,), (A::State,)>

where T: for<'a> FnMut(A::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static,

type System = OnceFunctionSystem<T, (A,), (<A as SystemParam>::State,)>

fn into_system(self) -> Self::System

impl<T> System for OnceFunctionSystem<T, (), ()>

where T: for<'a> FnMut() -> Option<()> + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A> System for OnceFunctionSystem<T, (A,), (A::State,)>

where T: for<'a> FnMut(A::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B> System for OnceFunctionSystem<T, (A, B), (A::State, B::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C> System for OnceFunctionSystem<T, (A, B, C), (A::State, B::State, C::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C, D> System for OnceFunctionSystem<T, (A, B, C, D), (A::State, B::State, C::State, D::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C, D, E> System for OnceFunctionSystem<T, (A, B, C, D, E), (A::State, B::State, C::State, D::State, E::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C, D, E, F> System for OnceFunctionSystem<T, (A, B, C, D, E, F), (A::State, B::State, C::State, D::State, E::State, F::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C, D, E, F, G> System for OnceFunctionSystem<T, (A, B, C, D, E, F, G), (A::State, B::State, C::State, D::State, E::State, F::State, G::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C, D, E, F, G, H> System for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C, D, E, F, G, H, I> System for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State, I::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>, I::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static, I: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C, D, E, F, G, H, I, J> System for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I, J), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State, I::State, J::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>, I::Item<'a>, J::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static, I: SystemParam + 'static, J: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C, D, E, F, G, H, I, J, K> System for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I, J, K), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State, I::State, J::State, K::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>, I::Item<'a>, J::Item<'a>, K::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static, I: SystemParam + 'static, J: SystemParam + 'static, K: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.

impl<T, A, B, C, D, E, F, G, H, I, J, K, L> System for OnceFunctionSystem<T, (A, B, C, D, E, F, G, H, I, J, K, L), (A::State, B::State, C::State, D::State, E::State, F::State, G::State, H::State, I::State, J::State, K::State, L::State)>

where T: for<'a> FnMut(A::Item<'a>, B::Item<'a>, C::Item<'a>, D::Item<'a>, E::Item<'a>, F::Item<'a>, G::Item<'a>, H::Item<'a>, I::Item<'a>, J::Item<'a>, K::Item<'a>, L::Item<'a>) -> Option<()> + 'static, A: SystemParam + 'static, B: SystemParam + 'static, C: SystemParam + 'static, D: SystemParam + 'static, E: SystemParam + 'static, F: SystemParam + 'static, G: SystemParam + 'static, H: SystemParam + 'static, I: SystemParam + 'static, J: SystemParam + 'static, K: SystemParam + 'static, L: SystemParam + 'static,

fn run(&mut self, _world: &World, _resources: &Resources)

fn requires(&self) -> Vec<RequiredResource>

Resource types this system needs present, derived automatically from its bare Res/ResMut parameters. App checks these before running a non-convergent stage’s systems and panics with a clear message naming the missing resource(s) rather than letting a param fetch panic deep inside whichever system happens to run first.

fn name(&self) -> &'static str

Human-readable identifier for this system, used in error/trace output so a missing-resource failure can be pinned to the system that needs it instead of just the resource name. Defaults to the type name of the System impl; FunctionSystem overrides this with the name of the wrapped function/closure, which is far more legible.