beet_flow 0.0.8

An ECS control flow library
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148

use crate::prelude::*;
use beet_core::prelude::*;

/// An action that runs all of its children in order until one fails.
/// ## Tags
/// - [ControlFlow](ActionTag::ControlFlow)
/// ## Logic
/// - If a child fails it will fail.
/// - If a child succeeds it will run the next child.
/// - If there are no more children to run it will succeed.
/// ## Example
/// Runs the first child, then the second child.
/// ```
/// # use beet_core::prelude::*;
/// # use beet_flow::prelude::*;
/// # let mut world = ControlFlowPlugin::world();
///	world.spawn((
/// 	Sequence,
/// 	children![
/// 		EndWith(Outcome::Pass),
/// 		EndWith(Outcome::Pass),
///    ]))
///		.trigger_target(GetOutcome)
/// 	.flush();
/// ```
#[action(on_start, on_next)]
#[derive(Debug, Default, Component, Reflect)]
#[reflect(Default, Component)]
#[require(PreventPropagateEnd)]
pub struct Sequence;

fn on_start(
	ev: On<GetOutcome>,
	mut commands: Commands,
	query: Query<&Children>,
) -> Result {
	let target = ev.target();
	let children = query.get(target)?;
	if let Some(first_child) = children.iter().next() {
		commands.entity(first_child).trigger_target(GetOutcome);
	} else {
		commands.entity(target).trigger_target(Outcome::Pass);
	}
	Ok(())
}

fn on_next(
	ev: On<ChildEnd<Outcome>>,
	mut commands: Commands,
	query: Query<&Children>,
) -> Result {
	let target = ev.target();
	let child = ev.child();
	// if any error, just propagate the error
	if ev.is_fail() {
		commands.entity(target).trigger_target(ev.value().clone());
		return Ok(());
	}
	let children = query.get(target)?;
	let index = children
		.iter()
		.position(|x| x == child)
		.ok_or_else(|| expect_action::to_have_child(&ev, child))?;
	if index == children.len() - 1 {
		// all done, propagate the success
		commands.entity(target).trigger_target(ev.value().clone());
	} else {
		// run next
		commands
			.entity(children[index + 1])
			.trigger_target(GetOutcome);
	}
	Ok(())
}

#[cfg(test)]
mod test {
	use crate::prelude::*;
	use beet_core::prelude::*;

	#[test]
	fn works() {
		let mut world = ControlFlowPlugin::world();

		let on_result = collect_on_result(&mut world);
		let on_run = collect_on_run(&mut world);

		world
			.spawn((Name::new("root"), Sequence, children![
				(Name::new("child1"), EndWith(Outcome::Pass)),
				(Name::new("child2"), EndWith(Outcome::Fail)),
			]))
			.trigger_target(GetOutcome)
			.flush();

		on_run.get().xpect_eq(vec![
			"root".to_string(),
			"child1".to_string(),
			"child2".to_string(),
		]);
		on_result.get().xpect_eq(vec![
			("child1".to_string(), Outcome::Pass),
			("child2".to_string(), Outcome::Fail),
			("root".to_string(), Outcome::Fail),
		]);
	}

	/// This test proves that observers are run in a breadth first order,
	/// the Sequence commands are captured, then the "root" is pushed to the store,
	/// then the children run. this means that multiple observers can be attached to the
	/// root and be guaranteed to run before the children.
	#[test]
	fn action_order() {
		let mut world = ControlFlowPlugin::world();

		let store = Store::<Vec<_>>::default();

		world
			.spawn((
				Sequence,
				OnSpawn::observe(move |_: On<GetOutcome>| store.push("root")),
				children![
					(
						Name::new("child1"),
						EndWith(Outcome::Pass),
						OnSpawn::observe(
							move |_: On<GetOutcome>| store.push("child1")
						),
					),
					(
						Name::new("child2"),
						EndWith(Outcome::Fail),
						OnSpawn::observe(
							move |_: On<GetOutcome>| store.push("child2")
						),
					),
				],
			))
			.trigger_target(GetOutcome)
			.flush();

		store.get().xpect_eq(vec![
			"root".to_string(),
			"child1".to_string(),
			"child2".to_string(),
		]);
	}
}