Struct bevy_ecs::system::StaticSystemParam
source · pub struct StaticSystemParam<'w, 's, P: SystemParam>(_);
Expand description
A helper for using system parameters in generic contexts
This type is a SystemParam
adapter which always has
Self::Fetch::Item == Self
(ignoring lifetimes for brevity),
no matter the argument SystemParam
(P
) (other than
that P
must be 'static
)
This makes it useful for having arbitrary SystemParam
type arguments
to function systems, or for generic types using the SystemParam
derive:
use bevy_ecs::system::{SystemParam, StaticSystemParam};
#[derive(SystemParam)]
struct GenericParam<'w,'s, T: SystemParam + 'static> {
field: StaticSystemParam<'w, 's, T>,
}
fn do_thing_generically<T: SystemParam + 'static>(t: StaticSystemParam<T>) {}
fn check_always_is_system<T: SystemParam + 'static>(){
bevy_ecs::system::assert_is_system(do_thing_generically::<T>);
}
Note that in a real case you’d generally want
additional bounds on P
, for your use of the parameter
to have a reason to be generic.
For example, using this would allow a type to be generic over
whether a resource is accessed mutably or not, with
impls being bounded on P: Deref<Target=MyType>
, and
P: DerefMut<Target=MyType>
depending on whether the
method requires mutable access or not.
The method which doesn’t use this type will not compile:
fn do_thing_generically<T: SystemParam + 'static>(t: T) {}
#[derive(SystemParam)]
struct GenericParam<'w,'s, T: SystemParam> {
field: T,
#[system_param(ignore)]
// Use the lifetimes, as the `SystemParam` derive requires them
phantom: core::marker::PhantomData<&'w &'s ()>
}
Implementations§
source§impl<'w, 's, P: SystemParam> StaticSystemParam<'w, 's, P>
impl<'w, 's, P: SystemParam> StaticSystemParam<'w, 's, P>
sourcepub fn into_inner(self) -> SystemParamItem<'w, 's, P>
pub fn into_inner(self) -> SystemParamItem<'w, 's, P>
Get the value of the parameter
Trait Implementations§
source§impl<'w, 's, P: SystemParam> Deref for StaticSystemParam<'w, 's, P>
impl<'w, 's, P: SystemParam> Deref for StaticSystemParam<'w, 's, P>
§type Target = <<P as SystemParam>::Fetch as SystemParamFetch<'w, 's>>::Item
type Target = <<P as SystemParam>::Fetch as SystemParamFetch<'w, 's>>::Item
source§impl<'w, 's, P: SystemParam> DerefMut for StaticSystemParam<'w, 's, P>
impl<'w, 's, P: SystemParam> DerefMut for StaticSystemParam<'w, 's, P>
source§impl<'world, 'state, P: SystemParam + 'static> SystemParam for StaticSystemParam<'world, 'state, P>
impl<'world, 'state, P: SystemParam + 'static> SystemParam for StaticSystemParam<'world, 'state, P>
type Fetch = StaticSystemParamState<<P as SystemParam>::Fetch, P>
Auto Trait Implementations§
impl<'w, 's, P> RefUnwindSafe for StaticSystemParam<'w, 's, P>where
<<P as SystemParam>::Fetch as SystemParamFetch<'w, 's>>::Item: RefUnwindSafe,
impl<'w, 's, P> Send for StaticSystemParam<'w, 's, P>where
<<P as SystemParam>::Fetch as SystemParamFetch<'w, 's>>::Item: Send,
impl<'w, 's, P> Sync for StaticSystemParam<'w, 's, P>where
<<P as SystemParam>::Fetch as SystemParamFetch<'w, 's>>::Item: Sync,
impl<'w, 's, P> Unpin for StaticSystemParam<'w, 's, P>where
<<P as SystemParam>::Fetch as SystemParamFetch<'w, 's>>::Item: Unpin,
impl<'w, 's, P> UnwindSafe for StaticSystemParam<'w, 's, P>where
<<P as SystemParam>::Fetch as SystemParamFetch<'w, 's>>::Item: UnwindSafe,
Blanket Implementations§
source§impl<T> Downcast for Twhere
T: Any,
impl<T> Downcast for Twhere
T: Any,
source§fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
Box<dyn Trait>
(where Trait: Downcast
) to Box<dyn Any>
. Box<dyn Any>
can
then be further downcast
into Box<ConcreteType>
where ConcreteType
implements Trait
. Read moresource§fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
Rc<Trait>
(where Trait: Downcast
) to Rc<Any>
. Rc<Any>
can then be
further downcast
into Rc<ConcreteType>
where ConcreteType
implements Trait
. Read moresource§fn as_any(&self) -> &(dyn Any + 'static)
fn as_any(&self) -> &(dyn Any + 'static)
&Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &Any
’s vtable from &Trait
’s. Read moresource§fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
&mut Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &mut Any
’s vtable from &mut Trait
’s. Read more