Type Definition specs::ReadExpect

type ReadExpect<'a, T> = Read<'a, T, PanicHandler>;

Allows to fetch a resource in a system immutably. This will panic if the resource does not exist. Usage of Read or Option<Read> is therefore recommended.

If the nightly feature of shred is enabled, this will print the type of the resource in case of a panic. That can help for debugging.

Trait Implementations

impl<'a, 'b, T> ParJoin for &'a ReadExpect<'b, T> where
    &'a T: ParJoin,
    T: Resource, 

fn par_join(self) -> JoinParIter<Self> where
    Self: Sized, 

Create a joined parallel iterator over the contents.

impl<'a, 'b, T> Join for &'a ReadExpect<'b, T> where
    &'a T: Join,
    T: Resource, 

type Type = <&'a T as Join>::Type

Type of joined components.

type Value = <&'a T as Join>::Value

Type of joined storages.

type Mask = <&'a T as Join>::Mask

Type of joined bit mask.

unsafe fn open(self) -> (Self::Mask, Self::Value)

Open this join by returning the mask and the storages.

unsafe fn get(v: &mut Self::Value, i: Index) -> Self::Type

Get a joined component value by a given index.

fn is_unconstrained() -> bool

If this Join typically returns all indices in the mask, then iterating over only it or combined with other joins that are also dangerous will cause the JoinIter/ParJoin to go through all indices which is usually not what is wanted and will kill performance.

Important traits for JoinIter<J>

impl<J: Join> Iterator for JoinIter<J> type Item = J::Type;

fn join(self) -> JoinIter<Self> where
    Self: Sized, 

Create a joined iterator over the contents.

fn maybe(self) -> MaybeJoin<Self> where
    Self: Sized, 

Returns a Join-able structure that yields all indices, returning None for all missing elements and Some(T) for found elements.