Struct Query 

pub struct Query { /* private fields */ }

Represents how to pull specific entities and components out of the world for use by a System. Methods in a Query can be chained to create more complex queries. All chains are treated like logical ANDs.

For example, the following Query:

use thomas::{Query, TerminalTransform, Identity, Component};

#[derive(Component)]
struct CustomComponent {}

Query::new()
    .has::<TerminalTransform>()
    .has_no::<CustomComponent>()
    .has_where::<Identity>(|identity| identity.id == String::from("PLAYER"));

Will match only for entities that have a TerminalTransform, AND do NOT have a CustomComponent, AND have an Identity component where its id property equals "PLAYER", .

Implementations

impl Query

pub fn new() -> Self

pub fn has<T: Component + 'static>(self) -> Self

Specifies that a matching entity must have the provided component to be a match for the query.

pub fn has_no<T: Component + 'static>(self) -> Self

Specifies that a matching entity may not have the provided component to be a match for the query. Regardless of any potential matches from has, if an entity has any component specified by any has_no calls on the query, that will entirely remove that entity from the ultimate list of matches.

pub fn has_where<T>(self, predicate: impl Fn(&T) -> bool + 'static) -> Self

where T: Component + 'static,

Specifies that a matching entity must have the provided component and the component must pass the provided predicate to be a match for the query.