Struct ParamBuilder

pub struct ParamBuilder;

A SystemParamBuilder for any SystemParam that uses its default initialization.

Example

fn my_system(res: Res<R>, param: MyParam, query: Query<&A>) {
    // ...
}

let system = (
    // A plain ParamBuilder can build any parameter type.
    ParamBuilder,
    // The `of::<P>()` method returns a `ParamBuilder`
    // typed as `impl SystemParamBuilder<P>`.
    ParamBuilder::of::<MyParam>(),
    // The other factory methods return typed builders
    // for common parameter types.
    ParamBuilder::query::<&A>(),
)
    .build_state(&mut world)
    .build_system(my_system);

Implementations

impl ParamBuilder

pub fn of<T: SystemParam>() -> impl SystemParamBuilder<T>

Creates a SystemParamBuilder for any SystemParam that uses its default initialization.

pub fn resource<'w, T: Resource>() -> impl SystemParamBuilder<Res<'w, T>>

Helper method for reading a Resource as a param, equivalent to of::<Res<T>>()

pub fn resource_mut<'w, T: Resource>() -> impl SystemParamBuilder<ResMut<'w, T>>

Helper method for mutably accessing a Resource as a param, equivalent to of::<ResMut<T>>()

pub fn local<'s, T: FromWorld + Send + 'static>() -> impl SystemParamBuilder<Local<'s, T>>

Helper method for adding a Local as a param, equivalent to of::<Local<T>>()

pub fn query<'w, 's, D: QueryData + 'static>() -> impl SystemParamBuilder<Query<'w, 's, D, ()>>

Helper method for adding a Query as a param, equivalent to of::<Query<D>>()

pub fn query_filtered<'w, 's, D: QueryData + 'static, F: QueryFilter + 'static>() -> impl SystemParamBuilder<Query<'w, 's, D, F>>

Helper method for adding a filtered Query as a param, equivalent to of::<Query<D, F>>()

Trait Implementations

impl Clone for ParamBuilder

fn clone(&self) -> ParamBuilder

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ParamBuilder

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ParamBuilder

fn default() -> ParamBuilder

Returns the “default value” for a type.

impl<P: SystemParam> SystemParamBuilder<P> for ParamBuilder

fn build(self, world: &mut World, meta: &mut SystemMeta) -> P::State

Registers any World access used by this SystemParam and creates a new instance of this param’s State.

fn build_state(self, world: &mut World) -> SystemState<P>

Create a SystemState from a SystemParamBuilder. To create a system, call SystemState::build_system on the result.

impl Copy for ParamBuilder