examples/queries/
query_without.rs

1use crate::z_ignore_test_common::*;
2
3use flecs_ecs::prelude::*;
4
5#[derive(Debug, Component)]
6pub struct Position {
7    pub x: f32,
8    pub y: f32,
9}
10
11#[derive(Component)]
12struct Npc;
13
14fn main() {
15    let world = World::new();
16
17    // Create a query for Position, !Npc. By adding the Npc component using the
18    // "without" method, the component is not a part of the query type, and as a
19    // result does not become part of the function signatures of each and iter.
20    // This is useful for things like tags, which because they don't have a
21    // value are less useful to pass to the each/iter functions as argument.
22    //
23    // The without method is short for:
24    //   .term<Npc>().not_()
25    let query = world.query::<&Position>().without::<&Npc>().build();
26
27    // Create a few test entities for the Position query
28    world.entity_named("e1").set(Position { x: 10.0, y: 20.0 });
29
30    world.entity_named("e2").set(Position { x: 10.0, y: 20.0 });
31
32    // This entity will not match as it has Npc
33    world
34        .entity_named("e3")
35        .set(Position { x: 10.0, y: 20.0 })
36        .add::<Npc>();
37
38    // Note how the Npc tag is not part of the each signature
39    query.each_entity(|entity, pos| {
40        println!("Entity {}: {:?}", entity.name(), pos);
41    });
42
43    // Output:
44    //  Entity e1: Position { x: 10.0, y: 20.0 }
45    //  Entity e2: Position { x: 10.0, y: 20.0 }
46}
47
48#[cfg(feature = "flecs_nightly_tests")]
49#[test]
50fn test() {
51    let output_capture = OutputCapture::capture().unwrap();
52    main();
53    output_capture.test("query_without".to_string());
54}
examples/queries/query_without.rs

examples/queries/
query_without.rs
