Macro with 

macro_rules! with {
    ($entity:ty) => { ... };
    ($entity:ty, $($prop:expr),+ $(,)?) => { ... };
}

Creates a query matching all entities of a given type, optionally filtered by properties.

Examples

// Add an entity with default properties
let query = with!(Person);
context.add_entity(query)?;

// An inline query matching a single property
let person = context.sample_entity(MyRng, with!(Person, Age(12)))?;

// A query matching multiple properties
let query = with!(Person, Age(12), RiskCategory::High);
let count = context.count_entities(query);